Fabíola A Camargo

Sylvie Janicot

Isabelle Sagnes

Arnaud Garnache

Patrick Georges

Gaëlle Lucas-Leclin

Evaluation of the single-frequency operation of a short vertical external-cavity semiconductor laser at 852 nm

Keywords: Semiconductor lasers, VECSEL, Thermal lens, Single-frequency

We present in this work the study of a short vertical external cavity semiconductor laser in single longitudinal operation at 852 nm without intracavity elements. Two different configurations were studied, a plane-plane configuration, stabilized by the thermal lens and a plane-concave configuration. The influence of the output coupler transmission and the thermal lens has been studied. In the plane concave configuration we have demonstrated more than 100mW in stable single frequency operation using a very compact cavity emitting around 852 nm.

INTRODUCTION

Stable single-frequency laser with narrow linewidth emission (< 500 kHz), fine tunability over a few GHz and output power in the 0.1 W range at 852 nm is required for the laser sources used in cesium atomic clocks. Until now different approaches have been studied in order to fulfill these properties : single frequency high power lasers have been demonstrated with distributed feedback diode lasers [START_REF] Klehr | High-power 894 nm monolithic distributed feedback laser[END_REF] and tapered extended cavity diode lasers [START_REF] Gilowski | Narrow bandwidth interference filter-stabilized diode laser systems for the manipulation of neutral atoms[END_REF]. However, these two solutions suffer from beam quality degradation at high power. A possible alternative solution to obtain a compact and simple single frequency source with narrow linewidth and good beam quality is an optically-pumped semiconductor vertical external-cavity surface-emitting laser (OPS-VECSEL) [START_REF] Kuznetsov | Design and characteristics of high-power (>0.5W CW) diode-pumped vertical-external-cavity surface-emitting semiconductor lasers with circular TEM 00 Beams[END_REF]. OPS-VECSEL's combine the benefits of solid-state lasers and laser diodes. It has the advantage of using a semiconductor as the gain medium which allows versatility in the wavelength emission. Moreover single-frequency, narrow linewidth, emission is obtained in simple and compact setups.

Watt-level, single frequency emission was demonstrated from OPS-VECSEL's at 1 µm [START_REF] Jacquemet | Single-frequency cw vertical external cavity surface emitting semiconductor laser at 1003 nm and 501 nm by intracavity frequency doubling[END_REF][START_REF] Laurain | Multiwatt-power highly-coherent compact single-frequency tunable Vertical-External-Cavity-Surface-Emitting-Semiconductor-Laser[END_REF], however few works have been done at 852 nm [START_REF] Hastie | 0.5-W single transverse-mode operation of an 850-nm diode-pumped surface-emitting semiconductor laser[END_REF][START_REF] Cocquelin | Tunable single-frequency operation of a diode-pumped vertical external-cavity laser at the cesium D2 line[END_REF]. Actually at this wavelength, GaAs/AlGaAs quantum wells (QW's) are used as the active layers, which present a lower optical gain; furthermore the high content of Aluminium in the barriers and in the Bragg mirror makes the semiconductor structure more sensitive to degradation. To date, output power in the 0.5 W range has been demonstrated under multilongitudinal mode operation, and the output power drops drastically in single-frequency operation due to the introduction of intracavity elements. Following the approach described in Ref. [START_REF] Laurain | Multiwatt-power highly-coherent compact single-frequency tunable Vertical-External-Cavity-Surface-Emitting-Semiconductor-Laser[END_REF], we investigate in this work the single-frequency emission of OPS-VECSEL's at 852 nm in short external-cavities without intracavity elements.

DESIGN OF A SHORT-CAVITY SINGLE-FREQUENCY VECSEL

Our aim is to develop a single-frequency VECSEL in the simplest possible configuration, without intracavity wavelength-selective filter and in a plane-plane cavity. This configuration was proposed in Ref. 8, and a stable singlefrequency, narrow linewidth emission with output power as high as 2.1 W at 1 µm was demonstrated [START_REF] Laurain | Multiwatt-power highly-coherent compact single-frequency tunable Vertical-External-Cavity-Surface-Emitting-Semiconductor-Laser[END_REF]. The proper design of such a laser source implies in one hand to get a clear understanding of the dynamics of the single-frequency operation, and on the other hand to evaluate the pump-induced thermal lens inside the structure, which contributes to the stabilization of the laser cavity.

Description of the active structure

The semiconductor structure which has been studied in this work is described in Figure 1; it has been grown by metalorganic chemical-vapor deposition on a 350 µm-thick GaAs substrate. It is designed for emission at λ L = 852 nm under barrier-pumping at λ ≤ 700 nm. The 30 λ/4-thick active region contains seven 8nm-thick GaAs QW's embedded within Al 22% Ga 78% As barriers, which absorb η abs = 86% of the incident pump power. The QW's are distributed among the optical standing-wave antinodes positions with a repartition 1-1-1-1-0-1-0-1-0-0-1 (from the top surface) which is calculated in order to provide a nearly constant excited carrier density among them. Two 30 nm-thick Al 39% Ga 61% As produce a potential barrier on each side of the active region for carrier confinement. The high-reflectivity Bragg mirror consists in 32.5 pairs of Al 22% Ga 78% As/AlAs layers, and absorbs the remaining pump power. A 20 nm-thick In 48% Ga52 % P protects the top surface of the structure from oxidation of the Al-rich barriers. Though in the following experiments the laser output power will be limited by the strong thermal roll-over induced by the low conductivity of the GaAs substrate, it should still be compatible with the requirements for metrology applications.

Single-frequency dynamical behavior

The active structure of a OPS-VECSEL has a nearly-ideal homogenous gain, which implies that the spectral bandwidth of the laser emission is simply driven by mode competition [START_REF] Garnache | Single-Frequency operation of External-Cavity VCSELs: Non-linear multimode temporal dynamics and quantum limit[END_REF]. The narrowing of the laser bandwidth Δν L with time, assuming a parabolic gain spectral profile, is described by Δν L t ( ) = Δν gain ln 2×τ ph t , with Δν gain the gain bandwidth, 𝜏 !! = 2𝐿 !"# 𝑐×𝐿 the intracavity photon lifetime, L ext the cavity length and L the total optical losses (output coupler and intracavity losses). When Δν L decreases below the free spectral range of the laser cavity, the laser collapses into one single longitudinal mode; the corresponding characteristic time t c for the single-frequency operation of the OPS-VECSEL is thus:

t c = 4 ln 2 cλ L 4 × L ext 3 Δν gain 2 L (1)
Experimentally, a stable single-frequency operation of a OPS-VECSEL will be obtained if t c is shorter than any typical technical fluctuations time (thermal and mechanical noise, or pump intensity fluctuations) of the laser cavity; then, after a perturbation arises, the laser shortly goes back to a single-frequency emission. Two approaches are possible to significantly decrease t c , either to decrease the gain bandwidth Δν gain by introducing wavelength-selective filters (etalon, birefringent filter), or to reduce the cavity length L ext . The first one is most commonly used, as it is simpler to implement, provides a wide wavelength tunability and allows the introduction of additional components (non-linear crystals, …). Nevertheless stable single-frequency operation of a short cavity OPS-VECSEL without intracavity wavelength filter has already been demonstrated [START_REF] Laurain | Multiwatt-power highly-coherent compact single-frequency tunable Vertical-External-Cavity-Surface-Emitting-Semiconductor-Laser[END_REF][START_REF] Cocquelin | Tunable single-frequency operation of a diode-pumped vertical external-cavity laser at the cesium D2 line[END_REF]. Here we investigate this solution for the realization of a single-frequency OPS-VECSEL emitting at 852 nm; with a cavity length L ext = 5 mm, optical losses L of about 3%, a gain bandwidth Δν gain = 3 20 nm, the characteristic time t c should be about 60 µs, which is actually below any typical fluctuations time (in the ms range), and is equivalent to the value calculated with a L ext = 25 mm long cavity and an intracavity filter with a bandwith Δν gain = 2 nm.

Evaluation of the thermal lens

Optical pumping of a gain medium, either semiconductor or crystal, induces a local increase of its temperature because of the amount of absorbed pump power that is converted into heat. The thermal fraction η th is the amount of incident pump power actually converted into heat, and is intrinsically limited by the quantum defect between the pump and the laser photon energies and the non-radiative transitions. Additionally in the active structure of a OPS-VECSEL, residual absorption of the pump power outside the gain region (Bragg mirror, substrate), also contributes to the heating of the active region. The thermal fraction is thus expressed as 𝜂 !! = 1 -𝜂 !"# 𝜂 !"# 𝜆 ! 𝜆 ! , with η abs the pump absorption in the gain medium, λ P and λ L the pump and laser wavelengths respectively, and η rad the radiative efficiency. In our structure, η th is evaluated to ~50% without laser emission, and ~35 % with laser emission.

In order to evaluate the temperature inside the semiconductor structure, we have first considered an analytical approach. Assuming a top-hat pump profile (waist radius W p ) and a bottom-side cooling, the maximum temperature rise, at the top surface of the structure, is estimated as ∆𝑇 !"# ≅ 𝜂 !! 𝑅 !! 𝑃 ! , with P p the incident pump power and R th the thermal resistance of the semiconductor structure. The latter is evaluated assuming a 1D-longitudinal cooling within the thin layers of the active region and Bragg mirrors (thickness e i , thermal conductivity κ i ), and a 3D cooling in the GaAs substrate; this hypothesis is valid as long as the pump waist radius W p is much smaller than the substrate thickness:

𝑅 !! = ! !! ! ! ! ! ! ! ! + ! ! ! !! ! (2)
From this expression, we estimate a thermal resistance R th = 230 K/W for a W p = 35µm pump spot, with as expected a major contribution (70%) from the GaAs substrate. For η th ×P p = 0.3 W of thermal power dissipated into the structure, the maximum temperature rise is thus ∆T max = 71 K. This analytical estimation has been compared to the value resulting from the numerical resolution of the heat transfer equation in the structure using a finite-element method (COMSOL Multiphysics). For this simulation, the semiconductor structure was described by three layers -active region, Bragg mirror, GaAs substrate -glued onto a copper heatsink with a 50 µm-thich heatpaste. The parameters of the simulation (layer thickness and conductivity) are given in Table 1. The cooper heatsink temperature is set to 15°C, and a cylindrical symmetry of the whole system is assumed. The temperature distribution inside the structure is shown in Figure 2. The temperature increase is maximum in the active region and reaches ∆T max = 59 K, which is in relative good agreement with our analytical estimation. The temperature distribution extends over a diameter of ~500 µm. The on-axis temperature remains almost constant among the active region (∆T(r=0) = 7 K). The main temperature difference is created inside the substrate, as expected from the analytical evaluation of the thermal resistance.

Thickness

Equivalent thermal conductivity

Active region 1.7µm 20 Wm -1 K -1 Bragg mirror 4.3 µm 34 Wm -1 K -1
GaAs substrate 350 µm 55 Wm -1 K - Thermal heatpaste 50 µm 2 Wm -1 K -1

Copper heatspreader 5 mm 400 Wm -1 K -1 The temperature radial gradient inside the gain medium generates a thermal lensing through different mechanisms: refractive index gradient, either directly thermally-induced or indirectly via the photoelastic effect, and bulging of the end faces resulting from thermo-mechanical stress [START_REF] Chénais | Thermal Lensing in Diode-Pumped Ytterbium Lasers-Part I: Theoretical Analysis and Wavefront Measurements[END_REF]. The major contribution in semiconductor-based active medium is the thermo-optic refractive index change [START_REF] Kemp | Thermal lensing, thermal management and transverse mode control in microchip VECSELs[END_REF], which depends on the thermal conductivity κ of the gain material, on its thermo-optic coefficient dn/dT × 10 -4 K -1 for the AlGaAs family) and on the cooling system configuration. The optical path difference experienced by the laser beam at λ L = 852 nm on one roundtrip in the active structure is expressed as:

Δ r ( ) = OPD 0 ( ) -OPD r ( ) = dn dt # $ % & ' (× T 0, z ( ) -T r, z ( ) * + , - 0 2d ∫ dz ≅ 2 dn dt # $ % & ' (d ΔT r, z = 0 ( ) (3)
The effective thickness d lens of the thermal lens is the laser penetration depth within the structure, which is estimated to d lens ~ 3.1 µm from the calculated laser field intensity profile along the layered structure. As the temperature does not change significantly inside the active structure over this thickness, the temperature distribution on the top layer of the structure will be simply considered for the evaluation of ∆(r). The radial profile of the optical path difference ∆(r) is simply deduced from the temperature profile, and a polynomial fit of its variation with radius is done. On the laser waist -approximately equal to the pump beam waist 2W P in our experiments -it exhibits a strong parabolic contribution associated with the thermal lens, but also a significant contribution of the 3 rd order spherical aberration (Figure 3).

Δ r ≤ W P ( ) ≅ r 2 2 f th + C r 4 W P 4 ( 4
)
For a thermal power P th = 0.3 W dissipated within the active structure (corresponding to an incident pump power of 0.6 W, below the laser threshold) and a W P =35µm top-hat pump beam profile, the focal length of the thermal lens is evaluated to f th ≅ 40 mm, which should correspond to the shortest focal length under our experimental conditions (see §3). The thermal lens f th varies inversely proportionally to the heat power η th ×P p and the thermal resistance of the structure R th .

Figure 3: Optical path difference experienced by the laser beam, on one roundtrip inside the laser cavity.

Cavity stability

We have investigated two laser cavities for the short-cavity OPS-VECSEL, with either a plane or a concave (R = 25 mm) output coupler. The cavity stability of these two configurations has been studied using the ABCD matrix formalism, and the laser waist radius W L on the active structure has been calculated as a function of the thermal lens f th (i.e. the pump power) and of the cavity length L ext . It follows the standard relationship for a 2-mirror cavity [START_REF] Siegman | Lasers[END_REF] :

W L = L ext λ L π g 2 g 1 (1-g 1 g 2 ) (5)
where g 1 = 1 -L ext /f th and g 2 = 1 -L ext /R 2 , f th is the thermal lens focal length and R 2 is the curvature radius of the output coupler. With no thermal lens and a cavity length L ext = 1 mm, the plane-concave cavity is stable and the laser waist W L is 36 µm. For minimum absorption losses, the laser waist radius W L should be smaller than the pump waist radius W P . In the following experiments, the pump waist is chosen as W P = 36 µm. From Figure 4, the plane-plane cavity is thus expected to operate for strong thermal lenses and short cavities, whereas the concave-plane setup is less sensitive to the thermal lens value for f th ≥ 40 mm.

EXPERIMENTAL CHARACTERISATION OF THE LASER EMISSION

Experimental setup

The active structure used for these experiments is described in section §2.1; it is glued with heatpaste on a cooper heatsink cooled by a Peltier element. The chip temperature is maintained at 15°C for all the following experiments. The pump source is a 5 W 690 nm fiber-coupled diode laser focused on the semiconductor using two doublets with focal distances of 60 mm and 40 mm, producing a pump beam waist W P = 36 µm in the chip. In order to obtain a good overlap between the pump and the laser beams and to ensure a circular laser beam, the pump beam is nearly perpendicular to the active structure; a slight angle between them prevents parasitic feedback between the pump fiber end and the laser. A dichroic mirror with high transmission at 690 nm and high reflectance at 850 nm is placed between the two doublets in order to separate the pump and the laser beams (Figure 5). Different output couplers with transmissions T = 0.7%, 2% and 3% are used; the radius of curvature of the concave output coupler is 25 mm.

Output power

In the plane-plane configuration, the maximum output power obtained is 95 mW for a 3% transmission (Figure 6). The laser threshold increases with the output coupler transmission T, from an incident pump power of 0.22 W (~5 kW/cm 2 ) with T = 0.7% to 0.36 W (~9 kW/cm 2 ) with T = 3%. Moreover the slope efficiency of the laser increases and reaches 61% for T=3%. Whatever the output coupler, the thermal roll-over occurs at an incident pump power of about 0.55 W. It is noteworthy that a stable laser operation of the plane-plane cavity is obtained at lower pump powers than expected from our study of the cavity stability based on the thermal lens ( §2.4): the focal length of the thermal lens at the incident pump power of 0.22 W is f th ~ 120 mm, corresponding to a laser waist approximately equal to W L =55 µm. As already mentioned in similar experiments [START_REF] Laurain | Multiwatt-power highly-coherent compact single-frequency tunable Vertical-External-Cavity-Surface-Emitting-Semiconductor-Laser[END_REF][START_REF] Kemp | Thermal lensing, thermal management and transverse mode control in microchip VECSELs[END_REF] and microchip solid-state lasers, gain-guiding of the laser emission may significantly contribute to the stability of the laser mode.

With the concave output coupler, a maximum output power of 102 mW is obtained for a transmission T=3%. Though the output power is similar in both setups, the laser threshold in this case is 0.15 W (~4 kW/cm 2 ); it is three times smaller in the plane-concave configuration, as the stability of the laser cavity is marginally dependent of the pump power contrary to the plane-plane configuration. In both configurations, the laser oscillates in the fundamental transverse mode (Figure 5, right), and is linearly polarized thanks to a slight gain anisotropy of our semiconductor structure.

Copper&heatsink!

L ext %≤%5%mm% 690nm%laser% diode%pump% λ&=&850&nm%

Dichroïc Mirror! HT@690nm! HR@852nm! f%=%60%mm% f%=%40%mm%

Output coupler!

GaAs!

Characterization of the laser spectrum

The spectrum is measured with an optical spectrum analyzer with a resolution of 10 pm, much smaller than the free spectral range of the laser, which is about 0.18 nm for a cavity length L ext = 2mm. On a wide range of operating parameters (cavity length L ext , incident pump power), the laser spectrum is single-frequency (Figure 7), with a side-mode suppression ratio > 35 dB. This confirms that single-frequency operation of a VECSEL can be obtained with a short cavity without any spectrally-selective intracavity element, thanks to the reduction of the characteristic time t c ( §2.2). We have finally characterized the stability of the laser line with a wavemeter; the wavelength is recorded every 200 ms during one hour. The relative variations of the laser wavelength are measured for the two cavity configurations, and with different output couplers. The laser line appears to be more stable for output couplers with a higher transmission, as expected from the expression of t c . Actually with the T=0.7% plane output coupler, the laser emission remains singlefrequency on a 20 mn time scale, but its wavelength exhibits a slow thermal shift with large instabilities in the neighborhood of a mode-hopping, every 0.18 nm. With the T = 3% plane output coupler, the fluctuations of the laser line remains ~ 9 pm (= 4 GHz) peak-to-peak (PP) on one minute, and ~ 100 pm (= 41 GHz) PP on one hour, without active stabilization of the cavity length (Figure 8). The laser line is even more stable with the concave output coupler, with T"="3%"

T"="0.7%" T"="2%" residual fluctuations of ~ 6 pm (= 2.5 GHz) PP on a 1 mn-scale, and 18 pm (= 7 GHz) PP on one hour (Figure 9). The lower wavelength stability of the plane-plane cavity can be attributed to its strong dependency to the pump power, and to the pump power fluctuations [START_REF] Laurain | Multiwatt-power highly-coherent compact single-frequency tunable Vertical-External-Cavity-Surface-Emitting-Semiconductor-Laser[END_REF].

Figure 1 :

 1 Figure 1 : Description of the active structure.

Figure 2 :

 2 Figure 2: Left -Temperature distributions inside the active structure through the various layers for the structure on GaAs substrate under optical pumping (η th ×P p = 0.3 W, W P = 35 µm); Right -Radial temperature profile (black line) at the top surface of the structure, and laser beam profile (dashed blue line).

Figure 4 :

 4 Figure 4: Laser beam waist in the semiconductor structure with the focal length of the thermal lens for a 1 mm long cavity (left) and with the cavity length for a thermal lens f th = 40mm (right).

Figure 5 :

 5 Figure 5: (left) Experimental setup for the short cavity OPS-VECSEL; (insert) Laser beam intensity demonstrating a fundamental transverse mode emission.

Figure 6 :

 6 Figure 6: (left) Laser output power as function of the input power in the plane-plane configuration for different output couplers transmissions; (right) Comparison of the laser performance between the two configurations (C-P : concave output coupler; P-P : plane output coupler) used for an output coupler transmission of 3%.

Figure 7 :

 7 Figure 7: Single frequency laser emission in the plane-plane configuration.

T

  OC #=#3%# published in Vertical External Cavity Surface Emitting Lasers (VECSELs) II -Proceedings of SPIE Conference 8242-14 (2012)

Figure 8 :

 8 Figure 8: Wavelength variation as function of time for different output couplers in the plane-plane configuration.

Figure 9 :

 9 Figure 9: Wavelength variation as function of time for the two configurations studied with a 3% transmission output coupler.

22 Ga 0.78 As/AlAs Active Layers 30λ/4 N QW = 7 GaAs QW L QW = 8 nm Barriers Al 0.22 Ga 0.78 As

	Energy
	Substrate
		Bragg Mirror
	GaAs 350 µm	Al 0.	32 pairs λ/4	Caping Layer GaAs + InGaP

published in Vertical External Cavity Surface Emitting Lasers (VECSELs) II -Proceedings of SPIE Conference 8242-14 (2012)

Table 1 :

 1 Parameters used for the calculation of the temperature map inside the structure.

published in Vertical External Cavity Surface Emitting Lasers (VECSELs) II -Proceedings of SPIE Conference 8242-14 (2012)

CONCLUSION

We have investigated the single-frequency operation of a short-cavity OPS-VECSEL emitting at 852 nm, dedicated to Cs atom spectroscopy. The single-frequency dynamics and the pump-induced thermal lens have been taken into account, to determine the optimum range of operation of the laser source. Experimentally, we have demonstrated a compact semiconductor laser emitting at 852 nm in single-frequency operation with more than 100 mW without intracavity elements. Stable single-frequency emission is demonstrated for output coupler transmissions higher than 2%, with no evidence of mode hopping for hours. Using a plane concave configuration the laser stability and the wavelength fluctuation is significantly decreased, below 6 pm on one minute, without active stabilization of the laser cavity. Further work to lock the laser line on a Cs atomic transition is in progress.

published in Vertical External Cavity Surface Emitting Lasers (VECSELs) II -Proceedings of SPIE Conference 8242-14 (2012)

ACKNOWLEDGMENTS

This work was supported by the French Agence Nationale de la Recherche (ANR-07-BLAN-0320-03). F. Camargo was funded by the RTRA/Triangle de la Physique (2010-089T).


Jan E M Houben

In view of the large number of misprints especially in the representation of the accents which are crucial in the argument (the signs

1.1

The Vedic Pravargya is a ritual that is optionally performed in connection with a Soma sacrifice. It is a unique Indo-Aryan development, without parallels in Iran or in areas of Indo-Europeans, and it can be traced back as far as 1500 B.C.E. (cf. Houben 2000a and b). The central object in the ritual is an earthenware pot that is placed on a fire until it is burning hot. At that moment the pot is identified with the sun, but also with the inner light of the inspired Vedic poet. As I argued recently (Houben 2006), the myths associated with the Pravargya do have Indo-European parallels, especially in Celtic stories on a magic cauldron (continued in the legend of the Holy Grail). Both in the Pravargya myths and in the Celtic and Arthurian stories there are recipients and cut-off heads identified or associated with the sun, and both are also associated with some (advanced) initiation or phase-transition in personal development. For the Pravargya the liturgies of all priests in a few distinct versions are available, and we also have quite elaborate descriptions both of the ritual and of the initiation (avāntaradīkṣā) to be undergone by the Veda-student when he wants to study the Pravargya-mantras.

1.2

We therefore have a reasonably detailed knowledge of the Pravargya, but the term used as its name has so far never been properly analysed and interpreted. pravargyà-may refer to the ceremony as well as to the heated pot. This pot has also other names, such as ghárma-'heat' and mahāvīrá-'great hero'. 2 The verb pra-vj is linked to the term pravargyà-and in appropriate contexts it means "to perform the Pravargya ritual" (e.g. TĀ 5.6.1-2). In a place such as KS 37.7: 88.2 pravargya-functions as the internal object of pra-vj (pravargyaḥ pravjyate). In Vedic ritual texts from the gveda onwards, pra-vj is also used in connection with placing and arranging the grass in the sacrificial area. However, with all the available indications for the structure and semantics of pravargyàit is still far from clear what might be the underlying meaning of the term on the basis of which it was taken as a name for the ceremony and the pot. It is not easy to determine this. Difficulties are: (a) pravargyà-is from the beginning exclusively attested in connection with this ritual; moreover, (b) the semantics of the verb vj and of compostions of vj with preverbs are notoriously problematic; finally, (c) there is the broader difficulty of ya-affixes (with various accentual properties) in verbal and nominal word-formation.

2.1

In an earlier publication (1991: 3 n. 3) I proposed to understand pravargyà-as "to be placed [sc., on the fire]," and I noted that it is "from pra-vj." This suits the character of the Pravargya ritual, it generally suits the gvedic occurrences of pra-vj, and it suits the use of pravargyà and its occurrence with pra-vj in later ritual texts.

2.2

It is moreover in accordance with Debrunner's discussion of the ya-affix and the future passive participle (gerundive 3 ), AiG § § 642-649. In § 642, Debrunner notes first (a) that, generally, -ya-(-tya-after brief vowels), in addition to having functions he discussed before, serves to form a gerundive; next (b), that in that case the root has very often zero grade; numerous examples are given, including, of direct interest to us, anapa-vjyá-'unfinishable', 'unending' (said of ádhvan-, roads, V 1.146.3); (c) that the root is also often in guṇa grade; numerous examples are given, among them bhógya-'to be enjoyed' (AV), márjya-'to be cleansed' (only V, and there only in the ninth maṇḍala), pari-vargyà 'to be avoided'; it is here that we find also mention of pra-vargyà-which Debrunner explains as 'a ceremony' ("e. Zeremonie"); the form is contrasted with pra-vjya which has the root in zero-grade; (d) the next category he mentions is those where the guṇa grade has a + simple consonant: here the a becomes long, e.g. grāhyà-, kāryà-; (e) verbs whose root ends in long ā (ai) have -eya-; finally (f, g, h), gerundives whereya-is attached to the verbal present stem and a few problematic cases. In § 644 the fluctuation between palatal and "guttural" -i.e., velar -final consonant of the root is discussed. Here, pra-vargyà-, with velar final consonant of the root, is again mentioned together with the contrasting form pra-vjya where the final root-consonant has remained palatal. The accent of words with gerundival -ya-is not discussed until § 654 where these are dealt with together with words that have other types of -ya-affixes.

2.3

This is also the direction followed by Michael Witzel when in 2004: xxix he gives what he considers the "literal" meaning of pravargyà-as 'the one to be turned towards (the fire)'. With this translation and his insistence that it is literal he suggests that pravargyà is indeed a future passive participle (gerundive) of the verb pra+vj taken in the meaning 'to turn towards'. The preverb prá (which is 'forward', 'forth'; 'towards' would in fact be pári) is a point which will be addressed later. First, let us ask whether the analysis of the form as a gerundive is indeed the best option, and whether the semantics of pra+vj makes sense with respect to the details of the Pravargya ritual.

3.1

Taking pravargyà-as a full-fledged gerundive is well possible, though it is not the only possibility. Debrunner lists pravargyà-among full-fledged gerundives in § 642, but he also notes that the velar final root-consonant points to a connection with an agent or action noun. 4 In addition, he shows that the velar is still rare in the V and the older literature, and that the forms with -ya-affix and velar final root-consonant can usually be paired with nouns in velar + -a-(e.g., upa-vākyà and upa-vāká).

3.2

According to Debrunner (AiG, p. 799), the velar is the general rule in the classical language. This statement he supports with a reference to Pāṇini's Aṣṭādhyāyī, A 7.3.52 cajoḥ ku ghiṇṇyatoḥ "instead of (the palatals) ca and ja there is a velar, if the affix has marker (it) GH or if the affix is ṆyàT." However, there are several exceptions to this rule 3 The gerundivum, also called verbal adjective (of nececity).

4

AiG II, 2 § 644.c, p. 799, Debrunner speaks of the "Zusammenhang der Gutturalformen mit dem Nomen ag. oder act," whereas there is "Zusammenhang der Palatalformen mit dem Verbum." Whitney 1889: 463 had already observed that in the later (classical) language "comes to be practically a primary one" but that many Vedic forms can be seen as secondary derivatives, and that in the case of, for instance, parivargyà-'to be avoided' and avimokyá-'not to be gotten rid of', "the guttural reversion clearly indicates primitives in ga and ka."

(mentioned by Debrunner), and the rule itself is limited in its application (only for affixes with GH-as marker and for the affix ṆyàT). Among the affixes indicated in this rule it is ṆyàT that would give -yà-with the desired accent, maintain the guṇa of the stem vowel produced by A 7.3.84, and would give velarization of the palatal by A 7.3.52, and thus lead to pravargyà-.

3.3

A different Pāṇinian way to derive pravargyà-, and hence a different way to analyse and understand the word, is by taking -yà-(yàT) as a secondary (taddhita-) affix. Added to pravargá-5 it yields pravargyà, and the meaning would be 'belonging to pravargá-', 6 'being in pravargá-' (A 4.3.53 tatra bhavaḥ), 'deserving pravargá-' (A 5.1.63 tad arhati). pravargá-itself can be derived from pra-vj with GHaÑ (which gives velarization of the palatal stop by A 7.3.52, the accent on the last syllable by A 6.2.143f).

4.1

For either of the two solutions we now need to know the exact meaning of pra-vj. While pravargyà-is attested only as term of the specific ceremony, pra-vj is used in different contexts and should hence be able to give some help. The V, which does not have the term pravargyà-as such, compares the action done with regard to the gharmá pot (in a ritual that corresponds to what later becomes the Pravargya) with another action that concerns the sacrificial grass.

nsatyābhyām barhír iva prá vñje stómā iyarmy abhríyeva vtaḥ / yv árbhagāya vimadya jāyṁ senājúvā nyūhátū ráthena // (V 1.116.1) I ... (prá vñje) for the two Aśvins, as one ... (prá vj ) the sacrificial grass, I set in motion the praises as the wind sets in motion the rain clouds, for you two, who brought to the small Vimada a wife, with your chariot, swift as an arrow. Geldner translated the first pāda as follows: "Für die Nāsatya's setze ich (den Milchtrank) ans Feuer wie das Barhis." Elsewhere, prá vj either refers to an action with sacrificial grass (V 7.2.4, 7.39.2) or to the ritual with the Gharma pot (V 5.30.15). V 7.2.4, for instance, is as follows:

saparyávo bháramāṇā abhijñú prá vñjate námasā barhír agnáu / ājúhvānā ghtápṣṭham pṣadvad ádhvaryavo havíṣā marjayadhvam // Geldner translates: "Sorgsam, indem sie es halb knieend bringen, legen sie unter Verneigung das Barhis um das Feuer. Begießet (das Barhis) und glättet das schmalzrückige, schmelzbutterige mit dem Opfer(schmalz), ihr Adhvaryu's!" Geldner's interpretation of prá vñjate as "um das Feuer ... legen" is problematic. "Put around (the fire)" is a meaning that is often mentioned for vj, but a critical confrontation with the ancient sources does not allow us to maintain that meaning, as demonstrated by Gonda 1985: 140-150. 7 In V 7.39.2a prá vāvje supray barhír eṣ ām, he translates the same 5

The word occurs in the V compound dāsá-pravarga-, V 1.92.8. 6 Debrunner AiG, p. 776, on the -ya-affix: "Seine Grundbedeutung war gewiß die allgemeine der Zugehörigkeit oder Beziehung." 7 Hoffmann 1967: 612 note "Im Vedischen heißt vj 'umwenden, herumlegen (pra vj an das Feuer setzen), abwenden, niederstrecken u.a.'." ;Mayrhofer 1996: 516;Werba 1997: 236. In his footnote 26 on p. 128, [START_REF] Gonda | The ritual functions and significance of grasses in the religion of the Veda[END_REF] still writes that "the first meaning of this verb (pravj-) is 'to pluck (break off, gather) and throw what has been plucked' (viz. the grass thrown round the fire, here called barhis, V 7.2.4; 7.39.2; in a transferred sense in V 1.116.24 of Rebha, who being tied (or covered with cords or strings) and pierced -verbs reminiscent of products of muñja grass, viz. strings and arrows -was thrown into the water but saved by the Aśvins); then the forms and derivatives of the verb appear to have been used also, in the same or a similar verb as "(ans Feuer) legen" (cf. also above, V 1.116.1): "Das Barhis ist (ans Feuer) gelegt, für sie angenehm zu betreten." In V 1.116.24 mention is made of a certain Rebha whom some persons had thrown in the ocean; he is said to be floating (víprutam) and právktam in the water.

4.2

After the V which does not yet refer to pravargyà-, the early Yajurvedic texts are the first to mention the ritual by this name. If anywhere, we can expect that here the name was not yet a petrified label for the specific ritual, that it retained its perspicuity, and that style and context can clarify how the term was understood. Already we saw KS 37.7: 88.2 with pravargya-functioning more or less as internal object of pra-vj: pravargyaḥ pravjyate. A text of the same tradition that is much more elaborate on the Pravargya is the KaṭhĀ. Although it is an Āraṇyaka it is not necessary that it is much younger than the Saṁhitā of its branch. The Pravargya was in any case a ritual that was already quite developed in the time of the gveda. An edition and German translation of the KaṭhĀ appeared in 1974 and was recently republished (with a new introduction) as Witzel 2004. KaṭhĀ 207+ of As the deities (here involved) are great and possess manly power, that is why (the pot in the ritual is called) Mahāvīra; as the bow did ghṅṅ, that is why (the pot in the ritual is called) Gharma. As it is .... that is why it is called the Pravargya. Witzel translates the last sentence: "Weil der (Gharmakessel) ans Feuer gestellt wird (pravjyate), deshalb der (Name) 'Pravargya'." However, "placing at the fire" does not have any support or resonance in the myth (arthavāda) that has just been told. After a lacuna in the manuscript the text continues (p. 80):

[... tébhir de]vḫ purástād yajñásya prvñjata. yát prvñjata, tásmāt právargyāni, tásmāt pravargyàs. tásmād, yás sápravargyeṇa yajñéna yájate, múkhyo brahmavarcas bhavat [i] ... With these (earlier mentioned formulae) the gods ... before the sacrifice. As they ... that is why (those formulae) are (named) Pravargya formulae, that is why (the ritual) is called Pravargya. That is why, if someone offers a sacrifice that is accompanied by the Pravargya, he becomes leader and full of the lustre of spiritual knowledge. ... Before the (main) sacrifice, the gods did something that amounted to doing the Pravargya; the one who, with reference to this, sacrifices (a big sacrifice) together with the Pravargya, he becomes chief. Witzel's interpretation of pra-vj as "putting on the fire" is again not very convincing. context, to indicate the throwing or placing of objects that have not been plucked." Apparently he wrote this note before having done the studies involved in the subsequent chapter X on Barhis (and section A on Barhis in the gveda).

4.3

Passages with a similar function are found in another Āraṇyaka, the Taittirīya-Āraṇyaka. Here it is Viṣṇu who first becomes proud of his success at the sacrifice and leans on his bow. The other gods arrange its string to be gnawed through.

tásya dhánur viprávamāṇaḥ śíra úd avartayat / tád dyvāpthiv ánu prvartata / yát prvartata / tát pravargyàsya pravargyatvám / yád "ghrā3" íty ápatat / tád gharmásya gharmatvám ... (TĀ 5.1.6) Stretching up, his bow caused his head to fly off. It proceeded along heaven and earth. That it proceeded (prāvartata), that is why the Pravargya is called Pravargya. That it flew off with the sound "ghraa," that is why the Gharma is called Gharma. ...

Here it is the preverb pra-that receives all emphasis in the explanation of the name Pravargya.

The TĀ also contains series of identifications of the pot used in the Pravargyaritual that allow us to determine with more precision at which stage in the ritual the author applies pra-vj. The first series (TĀ 5.11.1) is: "Prajāpati (is its name) when it is being collected (saṁbhriyámāṇaḥ); Saṁrāṭ when collected (sáṁbhtaḥ); Gharma when ... (právktaḥ); Mahāvīra when laying disposed (údvāsitaḥ)." The second series is: "Vaiśvadeva (is its name) when it is seated (on the throne). Vasus when ... (právktaḥ); Soma when being poured over (with ghee). Āśvina when the milk is poured in. Māruta when boiling. ... " etc.

4.4

The verb pra-vj is frequently used in connection with the Pravargya, from the gveda onwards where it refers to the gvedic predecessor of the Pravargya ritual. In the gveda it is also used in connection with grasses; there we have rejected the meaning "to put around (the fire)" that has frequently been attributed to it in that context. In post-gvedic sources pra-vj is also used in connection with the Pravaryga and there it has been translated regularly as "to put on the fire," which, however, seems a rough approximation of its sense that is often not convincing. Post-gvedic sources also have pra-vj in other contexts, of which I choose a more or less arbitrary example, the placing of the ukh or fire-pan in or at the Āhavanīya fire altar. Baudhāyana-Śrauta-Sūtra 10.13 says about this moment in the ritual the following: tasyā śakt piṇḍān pūtitṇānīti saṁprakīryājyasruvaṁ pratyasyāhavanīyasyāntameṣv aṅgāreṣu pravṇakti ... [i]ti dvābhyām / Kashikar's recent translation is as follows (2003: 569): "Having put into it [into the ukh or fire-pan, JH] dried balls of horse's faeces and dried grass, and having poured a spoonful of clarified butter, he burns it over the bordering embers of the Āhavanīya with two verses ... " This translation gives a good idea of what is going on, but it is clear that "burns it over" is not a literal translation of pravṇ akti. Āpastamba-Śrauta-Sūtra 16.9.4 deals with the same moment in the ritual in a slightly different statement, with less details: ... iti dvābhyām āhavanīye pravṇ akti. According to Gonda 1985: 128f, referring to these two passages, the priest "places (pravrṇakti) it in the embers in the proximity of the āhavanīya." It is more likely, however, that the ukh is indeed placed within the space of the Āhavanīya fire altar, but at its border, on glowing coals that are kept or placed there, a little away from the heart of the altar where the flames may be bigger. A passage like this may tempt us to believe that pravṇakti means "put on the fire" and in many cases this seems to work. But at other places it does not work, from the gvedic reference to Rebha onwards whom the Aśvins saved from the ocean.

5.1

One way to have access at the current meaning of a verb as it was understood by contemporaries, is to have a look at the simplest action noun derived from it (in Pāṇinian terms, the affix GHaÑ in the sense of bhāva-). The root tyaj has thus tyga-(alternatively tyāgá-), pac has pka-, sj has sárga-and vj is accompanied, in the living language, by the action noun várga-. The well-known word várga-'set', but also, more rarely, várga-as agent noun in the Kauṣītaki-Upaniṣad, "one who excludes or removes or averts," cf. MW s.v. várga, point to a dimension of the meaning of vj which has been largely overlooked. Starting from a basic meaning 'bend' scholars have arrived at 'putting around' and 'putting on the fire'. More suitable it would be to go from 'bend' not to 'put around' but to 'inflect' and 'set apart', 'set aside', either in a positive sense, or in a negative sense: 'exclude', 'avoid' (esp. in the compound pari-vj). With this move, all obscure places from the gveda onwards till the myths and other places dealing with the Pravargya in the sources of classical Vedic ritual become instantly clear.

The gvedic Rebha (V 1.116.24) was set apart and away, forward (prá-8 ), into the water (udáni, apsú), by his enemies and it was left to the Aśvins to save him from there (cf. V 1.112.5, 1.117.4). With our new understanding of pra-vj the first pāda of V 1.116.1 becomes now more convincingly: "I set apart or arrange separately, before or in advance (before the start of the main acts of the ritual) [viz., the Gharma pot], for the Aśvins, as one arranges separately or sets apart before or in advance (before the start of the main acts of the ritual, or in this case: in front, east of the Vedi, just behind the Āhavanīya 9 ) the sacred grass (barhís) ... " Similarly, in V 7.2.4b the priests "arrange separately or set apart in front (before the main ritual; or in front, just behind the Āhavanīya) the Barhis, at the (Āhavanīya) fire, with obeisance ... "

5.2

In the Kaṭha-Āraṇyaka origin myth of the Pravargya (KaṭhĀ 207+), we have seen that "is placed on the fire" is not a fully satisfactory translation of pravjyáte in yát pravjyáte, tásmāt pravargyàḥ. Rather we translate: "As (the pot) is arranged separately before (the main ritual), that is why (the pot is called) Pravargya." This statement now suddenly resonates with the immediately preceding myth: in the ritual the pot -in accompanying mantras said to be the "head" of the sacrifice, and identified with the sunis arranged separately, in the myth it was Rudra's head that was "set apart" and became the sun. Similarly, in the succeeding passage, tébhir devḫ purástād yajñásya prvñjata ... tásmāt právargyāni, tásmāt pravargyàḥ: "With these (earlier mentioned formulae) the gods arranged separately the pot 10 before the sacrifice. As they arranged this separately in advance, that is why (those formulae) are (named) Pravargya formulae, that is why (the ritual) is called Pravargya." Here, purástād yajñásya explains the pra-in pra-vj and in 8 Pirart's proposal (1995: 196) to emend prá-vkta-here to prá-vta-(against the metre!) is based on the acceptance of wrong meanings for pra-vj, and can be safely rejected. The passages discussed by Gonda suggest to me that after the general strewing (st) on the Vedi some grass is arranged separately (pra-vj-), for instance just behind the Āhavanīya. Gonda 1985: 150 is more careful: "The information the gvedic texts give on the spot where the barhis is spread is scanty. There is only one place where it is most probably said to have been put on the vedi (2.3.4), but it does not follow that ... this was the only, or even the usual place ... [The texts do not] in spite of Geldner's translations, explicitly state that the barhis is strewn around the fire. ... In any case, ... it could be placed, for instance between the fire and the vedi." 10 Because of the preceding lacuna it is not clear whether the gods are already involved with the Pravargya-pot or with something else.

pravargyà. Only with this interpretation it makes sense for the author to continue with the statement that "if someone offers a sacrifice that is accompanied by the Pravargya, he becomes the leader (múkhya) …" The importance attributed by early contemporary authors to the pra-of pra-vj and of Pravargya is also clear from the discussed passage in TĀ 5.1.6. In the series of identifications in TĀ 5.11 the episodes where the Pravargya pot is said to be právktaḥ corresponds with the moment it is placed on the fire, but this is also the moment it is placed apart, a little aside of the area where the main acts of the sacrifice are being performed, on the special pravñjanīya-khara-, the special mound for the pot when it is set apart.

In the case of the ukh or fire-pan, it is said (BŚS 10.13 and ĀpŚS 16.9.4) that the priest prav ṇ akti this pan in the Āhavanīya (ĀpŚS) or, more precisely, on the bordering embers of the Āhavanīya as the BŚS explains (āhavanīyasyāntameṣv aṅgāreṣu pravṇakti). One misses the point if pravṇ akti is understood as "to place in the fire": the pan is placed in a specific way, by keeping it apart, at the side of the altar-space, away from the center where higher flames can be expected. pravṇakti is then: arranged separately, placed and kept apart (at the 11 6.

If the verb vj is 'to set apart', 'seclude' and pra-vj 'to set apart', 'arrange separately in front or in advance', what is then pravargyà-? As we have seen, we have two possible routes to arrive at this form: as primary derivative from pra-vj it is "that which is to be set apart, to be arranged separately, before (the main ritual)"; as secondary derivative from pravargá-it is "that which belongs to, which remains in, or which deserves, an excellent (pra-) secluded class." 12 In both cases the name pravargyà-directly expresses, to anyone familiar with Sanskrit and with Vedic ritual, the core of the Pravargya: the seclusion of the pot, and, in the Avāntaradīkṣā which the eligible priest has to have undergone in advance, the seclusion of the Veda-student. On the other hand, the meaning with which modern scholarship got stuck, "to be put on the fire" would be a platitude in a ritual system where all major offerings are usually prepared and almost always offered in the fire.

With regard to the word which differs only in the preverb, pari-vargyà-, the preceding discussion implies that it is either directly derived from pari-vj and means 'to be avoided', 'to be excluded'; or it is derived from pari-vargá 'avoidance' and means 'being in the category of exclusion', 'deserving avoidance'. On the other hand, a word such as vāsudeva-várgya-'belonging to the group of (devotees of) Vāsudeva' (the grammarians' example to illustrate A 6.2.131) admits only of an interpretation as 11 Other problematic passages with pra-vj become clear with 'set aside', 'set apart', 'seclude' as basic meaning of vj. In the Jaiminīya-Brāhmaṇa forms of pra-vj occur several times without reference to the sacrificial fires. Bodewitz, observing that "to put on the fire" does not suit in such places, proposed in a footnote "exclude or throw out " (1973: 119) if sa kiṁ vidvān pravñjyât (JB 1.46) says something about the Season, interrogating the deceased. Similarly, in JB 1.61 pra-v apparently amounts to 'exclude', 'keep out' (Bodewitz 1973: 198f). Again, in JB 1.120 na bhatyā vaṣaṭkuryāt pa śūnā[m] apravargāya / yad bhatyā vaṣaṭkuryād vajreṇa vaṣaṭkāreṇa paśūn pravñjyāt , pra-vj is not 'ins Feuer werfen ' with Caland (1919: 28), nor 'strike down' with Bodewitz (1990: 68, cf. 241), but 'to set apart, exclude'; similarly, apravargāya in the cited passage is "in order not to exclude, not to put aside (viz., the cattle)." 12 pravargá-in exactly this sense occurs in V 1.92.8 in the compound dāsá-pravarga-"(wealth) that has as its first class slaves," "(wealth) the first category of which is slaves," or "(wealth) consisting of slaves, to begin with." secondary derivative. The presence of these words and these formations in the language ensure that the word pravargyà-was indeed understood as a meaningful name, not as an empty label for an obscure Vedic ritual.

  9

  this edition (p. 78) is as follows: rudráṁ vái dev yajñn nírabhajan. sá dhánur avaṣṭ ábhyātiṣṭhat. tásyéndro vamrirūpéṇa dhanurjym aśchinat. s ghṅṅ akarot. tásyrtiś [rtniś ?] śíra útpipeśa. sá pravargyò 'bhavad. yán mahatr devátā vīryàvatīs, tásmān mahāvīró. yád dhánur ghṅṅ ákarot, tásmād gharmó. yát pravjyáte, tásmāt pravargyà[ḥ].The gods excluded Rudra from the sacrifice. He stood leaning on his bow. Indra, in the form of an ant, cut the bow string. It (the bow string) made the sound "ghṅṅ ." The end of his bow beat his head upwards. That became the Pravargya.

Abbreviations AiG = Altindische Grammatik of J. Wackernagel and A. Debrunner (vol. II,2): see [START_REF] Debrunner | Altindische Grammatik[END_REF]. ĀpŚS = Āpastamba Śrautasūtra BŚS = Baudhāyana Śrautasūtra. JB = Jaiminīya-Brāhmaṇa. KaṭhĀ = Kaṭha-Āraṇyaka. KS = Kāṭhaka-Saṁhitā. MW = Monier Monier-Williams' Sanskrit-English Dictionary, Oxford, 1899. V = gveda. TĀ = Taittirīya-Āraṇyaka.


This paper presents a descriptive overview and formal analysis of the use of pronominal clitics for realizing various types of arguments in Persian, with particular emphasis on object clitics in the verbal domain. We argue that pronominal clitics behave more like suffixes than independent syntactic elements; in cases where they take syntactic scope over an NP or a PP, they must be phrasal affixes. We propose an HPSG analysis to account for the morphosyntactic aspects of verbal suffixation of object clitics, possessive clitics, preverbal object clitics, and clitic doubling constructions. Finally, we explore extensions of the analysis to periphrastic verb forms, and we compare our proposals for Persian to previous HPSG work on clitic phenomena in other languages.

Introduction and data 1.Forms and functions

Persian has two sets of personal pronoun forms: full forms (1a) and enclitic forms (1b) (Lazard, 2006, §87, §91). 1 (1) a. 2 -at (-et) -etân (-etun) 3 -aš (-eš) -ešân (-ešun) Full pronouns and enclitic pronouns can be used, often interchangeably, to express nominal arguments in a variety of constructions, but their morphosyntactic properties are highly divergent. We will consider two kinds of pronominal functions. First, pronouns can be used to realize the nominal argument of a noun, adjective, or preposition: 2 Second, pronouns can be used to express an argument of a verb. 3(4) a. (mâ) we

Maryam-râ Maryam-DDO did-im saw-1PL / (mâ) we u-râ PRO.3SG-DDO did-im saw-1PL 'We saw Maryam.' / 'We saw him/her.' b. (mâ) we did-im-aš saw-1PL-3SG 'We saw her/him/it.' Again, the full pronoun u has an NP-like distribution, very different from that of the enclitic -aš, which in this case is attached directly to the verb.

Clitic doubling is possible in colloquial registers. In other words, a single argument can be realized simultaneously as a syntactic complement (ordinary NP or full form pronoun) and as a clitic on the verb.

(5) Maryam-râ Maryam-DDO did-im-aš saw-1PL-3SG / u-râ PRO.3SG-DDO did-im-aš saw-1PL-3SG 'We saw Maryam.' / 'We saw him/her.'

Preverbal object clitics

Instead of appearing with the verb as in the previous examples, object clitics can be realized on a variety of hosts to the left of the head verb. For example, Persian has a large number of compound predicates consisting of a lexical verb and a "preverb", typically a noun, adjective, or adverb that can be treated as a kind of grammaticalized complement. A direct object clitic can appear on either one of these elements: An object clitic can also attach to a phrasal host, in most cases a PP:

(7) a. Although they are attached to a host on their left, preverbal object clitics are also subject to a strong contextual constraint to their right: they must be immediately followed by the head verb. In the following example, the object clitic can attach to the preverb nešân, but not to the preceding PP complement:4 (12) a.

(ketâb-hâ-râ) book-PL-DDO As this previous example illustrates, beneficiary arguments can sometimes be realized as object clitics. This possibility is quite restricted, however, and it may be related to the fact that with some verbs, the beneficiary argument can be realized either as a be-PP as in (13a), or as an accusative NP (Lazard, 2006, §176.1). The constraints governing these alternations are not completely understood. We note furthermore that PP complements disallow clitic doubling:

(14) * ketâb book

[ PP be to to PRO.2SG ] nešan-at show-2SG dâd-im gave-1PL / /
nešan show dâd-im-at gave-1PL-2SG (intended) 'We showed a book to you.'

Arguments for affixal status

It is rarely straightforward to decide whether a clitic-host sequence should be analyzed syntactically or morphologically, because by definition, clitics present a combination of word-like and affix-like properties. In this section, we will review a number of phonological and morphological facts that suggest strongly that pronominal enclitics in Persian are best analyzed as suffixes.

Phonological effects

Certain phonological adjustments can be observed when a vowel-initial pronominal clitic attaches to a vowel-final host. Some vowel sequences (e.g. i-e, i-a, e-a) are allowed (15a), but in other cases, the hiatus is broken by the insertion of the glide y:

(15) a. gorbe + aš → gorbe-aš 'his/her cat' b. pâ + -aš → pâ-yaš 'his/her foot' c. pâ + -emân → pâ-yemân 'our foot'

In colloquial Persian, the initial vowel of the clitic is often elided in such cases:5

(16) a. pâ + -eš, pâ + -emun → pâ-š, pâ-mun 'his/her foot, our foot' b. did-i + eš → did-i-š 'saw-2SG-3SG' ❀ 'you saw him/her/it' Similar effects can be found with other clitics and at other morpheme boundaries. For example, glide insertion occurs before the ezafe linking vowel and before subject agreement markers. 6(17) a. xâne + -e → xâne-ye 'house-EZ' b. mi-farmâ + -ad → mi-farmâ-yad 'IPF-order-3SG' ❀ 'he orders'

In contrast, such effects are not observed at the boundary between two syntactic words. For example, there is no glide insertion between a preposition and its NP object:

(18) bâ âb / *bâ y-âb; tu âb / *tu y-âb 'with water; in the water'

While the foregoing examples show that pronominal clitics are more closely bound to their hosts than the elements in an ordinary syntactic combination, these facts are not wholly incompatible with a syntactic approach. A pronoun like -aš could be taken to be a syntactic word with a special marking like [+CLITIC] (to distinguish it from the full pronoun u 'he/she'). This marking could then license the phonological adjustments described above (vowel elision and glide insertion) as productive, "low-level" strategies for resolving hiatus.

This approach runs into difficulties, however, with the following data, involving prepositions. In colloquial Persian, some prepositions can combine with a clitic object, as we saw in (3) above. 7 The prepositions be and bâ exhibit unexpected morphophonological effects with clitic objects. The initial vowel of the clitic can be elided (19a), just as in ( 16) above. Glide insertion, however, is not possible (19b); instead, we find idiosyncratic forms containing an inserted h (19c).

(19) a. be + -eš, bâ + -emun → be-š, bâ-mun 'to him, with us' b. *be-yeš (*be-aš), *bâ-yemun (*bâ-yemân) c. be-heš, bâ-hâmun We could assume, following de Fouchécour (1981, p. 82), that these two prepositions have long forms behe and bâhâ, used exclusively with [+CLITIC] complements (while the forms be and bâ are compatible with all types of complements). But this would not explain why only vowel elision can apply to the resulting syntactic combinations, and not glide insertion. We prefer to analyze these preposition + clitic sequences as grammaticalized morphological compounds, for which such gaps and idiosyncrasies are more typical and can be dealt with in terms of familiar morphological notions such as allomorphy, suppletion, and defectivity.

Co-occurrence constraints

It is clear from the examples we have seen up to now that pronominal clitics allow "promiscuous attachment" to a wide range of hosts, in particular phrasal hosts. This could be taken as an argument in favor of syntactic combination. We will show in this section, however, that clitics are in fact sensitive to the lexical and morphological properties of their hosts, and that these facts cannot always be accounted for by syntactic means, such as subcategorization.

First of all, let us consider some cases that are potentially compatible with a syntactic approach. Participles, for example, can combine with a (possessive) pronominal clitic when used adjectivally (20a), but in verbal constructions they cannot host object clitics (20b): The syntactic analysis could still be saved, for example by introducing further features to distnguish clitics on the verb and preverbal clitics, but we prefer to treat the ungrammaticality of ( 20b) and (21b) as a morphological fact: pronominal clitics are suffixes, and the verb forms in these examples are simply incompatible with this type of suffixation.

Other systematic restrictions on pronominal enclisis present even more problems for the syntactic approach. As we saw above in (13c-d), there can be at most one pronominal clitic per host. This is true even if the clitics have distinct syntactic functions and scope. Compare, for example, sentence (7b), repeated here as (22a), and (22b), in which the PP complement happens to end with a possessive clitic:

(22) a.

[ PP ru-ye on-EZ miz table

] -aš -3SG gozâšt-im put-1PL (= 7b) 'We put it on the table.' b. * [ PP ru-ye on-EZ miz-at table-2SG ] -aš -3SG gozâšt-im put-1PL (intended) 'We put it on your table.'
clitic is distinct from the subject agreement suffixes found with other verb forms, although the two paradigms are nearly identical:

(i) a. subject agreement suffixes: b. enclitic auxiliary budan:

sg pl 1 -am -im 2 -i -id (-in) 3 -ad (-e) -and (-an) sg pl 1 -am -im 2 -i -id (-in) 3 -ast (-e) -

and (-an)

Note also that the 1sg form in both paradigms is identical to the 1sg object clitic, -am (1b). To avoid confusion, no examples with 1sg subjects are used in this paper.

Under a syntactic analysis, the clitic -aš combines with a PP in both cases, and given standard assumptions about locality, it should not be sensitive to the detailed morphological structure of a particular word within the PP. On the other hand, if -aš is a suffix, i.e. morphologically integrated into the right-most word of the host PP, then the contrast between miz-aš and *miz-at-aš can be explained straightforwardly at the lexical level, by formulating restrictions on multiple suffixation.

Pronominal clitics also cannot co-occur with ezafe, which we have already encountered in several examples. This linking element, with the form (y)e, licenses the realization of NP-internal dependents to the right of the head noun. Following [START_REF] Samvelian | A phrasal affix analysis of the Persian Ezafe[END_REF], we treat ezafe as a phrasal suffix. In example (23a), the noun lebâs must carry this suffix in order to combine with the adjective sefid, and the resulting phrase must be suffixed in order to combine with a possessive NP or full pronoun. In contrast, the second ezafe must not appear if the possessive pronoun is realized as a clitic (23b). ( 23 The fact that no ezafe appears on the adjective in (23b) indicates clearly that -aš is not a syntactic dependent within the NP. Instead, it is a suffix that attaches to the adjective morphologically (although, as a phrasal affix, it has syntactic and semantic scope over the whole NP). [START_REF] Samvelian | A phrasal affix analysis of the Persian Ezafe[END_REF] demonstrates that pronominal clitic + ezafe sequences are also excluded. In the following example, the relative clause must take ezafe to allow the realization of the genitive/possessive NP in dâstân 'of this novel' to the right. This is impossible in (24a), however, because the last word of the relative clause, mihan-aš 'his homeland', already carries a pronominal suffix: Again, these facts would be difficult to analyze if -aš and -(y)e were syntactic elements, but they are readily explained if we assume that both forms are suffixes that cannot appear simultaneously on the same word.

Extraction

A last piece of evidence for the affixal status of pronominal clitics involves extraction. An object clitic must be fronted along with its host constituent (25b): The clitic cannot simply be stranded and attach to a new host (25c).9 And unsurprisingly, the clitic cannot be fronted without its host (25d). These facts are not wholly incompatible with an analysis of clitics as specially marked [+CLITIC] syntactic elements, with several additional assumptions and stipulations. But they follow automatically if baz-aš is analyzed as a single word (that is nevertheless interpreted as realizing two separate arguments of the verb).

In section 1.2, we stated that preverbal clitics had to immediately precede the verb; recall example (12). We can see now that this constraint is both too strong and too weak. Too strong, because the fronted clitic in (25b) is exempt from this constraint. Too weak, because the ungrammatical example (12b) remains ungrammatical even if the preverb nešân is extracted: The correct generalization appears to be, therefore, that preverbal clitics must be hosted by the least oblique complement of the verb, and that within the clause (i.e. if they are not extracted along with their host) they must appear immediately before the verb.

HPSG analysis of object clitics

Morphophonological functions

We adopt the insights of Miller and Sag (1997) in order to analyze the morphological realization of pronominal clitics as affixes. We briefly review the original analysis of French clitics, before presenting our proposed extension of the model to the Persian data.

Miller and Sag treat subject and object pronominal clitics in French as affixes on the verb. A sentence like Je vous les donne 'I give them to you' is thus analyzed as a single syntactic word, consisting of the finite verb donne and three pronominal affixes: Je-vous-les-donne.

The key technical device in their analysis is the morphophonological function F PRAF , which takes as input the inflected form of the verb (in I-FORM), its HEAD value (which determines prefixal vs. suffixal realization of pronouns), and its ARG-ST value. Elements on the ARG-ST list are typed as either canonical-or affixsynsem objects, and of course they carry grammatical specifications like the case and agreement features of each argument. Given this information, F PRAF outputs the appropriate phonological form for the cliticized verb.

(27) clitic-wd →         MORPH FORM F PRAF ( 0 , 1 , 2 ) I-FORM 0 SYNSEM   LOC | CAT HEAD 1 ARG-ST 2          
For Persian, we propose a similar function, F pron , which requires four parameters instead of three. These include, of course, the I-FORM of the host and its ARG-ST list. The HEAD value is also necessary, not to determine the position of pronouns (unlike in French, Persian pronouns are always suffixed) but because F pron is defined for both verbal and non-verbal hosts. Finally, the fourth parameter is the EDGE | RIGHT value, which contains the PRONARG feature, whose function will be explained in section 3.3 below.

(28

)            MORPH FORM F pron ( 1 , 2 , 3 , 4 ) I-FORM 1 SSM | LOC | CAT      HEAD 2 ARG-ST 3 EDGE | R 4 PRONARG index ∨ none                

Suffix appearing on the verb

The following examples involve the inflected ditransitive verb gozâšt-im 'we put', for which we assume the following basic lexical description:10 (29) gozâšt-im 'put-1PL' ❀ 'we put'

           MORPH FORM F pron ( 1 , 2 , 3 , 4 ) I-FORM 1 gozâšt-im HEAD 2 verb ARG-ST 3 NP 1pl , NP[acc], PP EDGE | R 4 PRONARG none           
For our purposes, the I-FORM value can be a simple phonological string, but in actuality it contains a richer morphological representation. 11 In this description, the verb's accusative NP argument and its PP argument are underspecified, so the value of F pron is as yet undetermined.

In the first example, the ARG-ST list in ( 29) is instantiated to require a canonical PP argument, but an NP argument of type affix-synsem with 3sg agreement features.

(30) gozâšt-im-aš 'put-1PL-3SG' ❀ 'we put it'

      FORM F pron (gozâšt-im, verb, 3 , [PRONARG none]) = gozâšt-im-aš ARG-ST 3 NP 1pl , NP 3sg [aff ], pp PP[canon] COMPS pp      
Given an ARG-ST of this form as input, the effect of F pron is to add the suffix -aš to the inflected verb. Following HPSG argument mapping principles, non-canonical synsem objects such as affixes are not mapped to the valence lists. In this case, the affix NP is not mapped to COMPS and therefore will not give rise to an additional, syntactic realization of the direct object. The PP argument, on the other hand, is mapped to COMPS and therefore realized canonically:

(31) [ PP ru-ye on-EZ miz] table
gozâšt-im-aš put-1PL-3SG 'We put it on the table.' Recall from example (5) above that clitic doubling is observed in colloquial Persian. To account for this, F pron adds an optional pronominal suffix corresponding to a canonical argument: 12 (32) gozâšt-im(-aš) 'put-1PL(-3SG)' ❀ 'we put'

      FORM F pron (gozâšt-im, verb, 3 , [PARG none]) = gozâšt-im(-aš) ARG-ST 3 NP 1pl , np NP[canon], pp PP[canon] COMPS np , pp      
In this case, the verb may be suffixed, but the NP argument is still mapped to COMPS and gives rise to the realization of a syntactic complement:

(33) ketâb-râ book-DDO

[ PP ru-ye on-EZ miz] table
gozâšt-im(-aš) put-1PL(-3SG) 'We put the book on the table.'

Suffix appearing on a non-verbal host

Pronominal clitics can also attach to nouns and adjectives and some other nonverbal categories. In the general case, the host is a phrase, but in HPSG, syntactic phrases cannot undergo suffixation. A lexicalist analysis of phrasal affixation is possible, though, if we separate the morphological effects of the suffix (at the lexical level) and its syntactic and semantic effects (at the phrasal level).

The morphological realization of clitics on non-verbal hosts is exactly the same as in the case of verbal suffixation, so it is handled by the same function F pron . The following example illustrates the suffixation of the 3sg suffix -aš to the adjective sefid 'white':

(34) sefid-aš 'white-3SG'

          MORPH FORM F pron ( 1 , 2 , 3 , 4 ) I-FORM 1 sefid HEAD 2 adj ARG-ST 3 EDGE | R 4           ❁       MORPH FORM F pron ( 1 , 2 , 3 , 4 ) = sefid-aš EDGE | R 4   PRONARG PER 3rd NUM sg        
Unlike the examples in the previous section, F pron does not constrain the host's ARG-ST list (which in this case is empty). The only constraint that F pron imposes is that the presence of the suffix (i.e. its 3sg index) must be recorded in PRONARG. We introduce this feature to handle the mismatch between the morphological scope of the suffix (a single word) and its syntactic/semantic scope (a phrase or clause).

into the grammatical description and added as an additional parameter to Fpron.

To see how this works, consider our analysis of example (23b) above. 13(35) [ NP lebâs-e sefid] -aš 'dress-EZ white-3SG' ❀ 'her white dress'

NP   ARG-ST 0 NP i [aff ] R | PRONARG none   NP   ARG-ST 0 R 4 PRONARG i 3sg   ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ✭ ✭ ✭ ✭ ✭ ✭ ✭ ✭ N   ARG-ST 0 (NP) R | PRONARG none   lebâs-e A   ARG-ST R 4 PRONARG i 3sg  

sefid-aš

As we have just seen, the suffixed adjective sefid-aš has a non-empty PRONARG value, but at the lexical level, the interpretation of this 3sg index is not yet determined. The common noun lebâs has an optional NP argument on its ARG-ST list (linked to a possessive relation in its semantic content), which is also uninstantiated at the lexical level. These two pieces of information can only be associated when the entire phrase lebâs-e sefid-aš is constructed. This is why we defined PRONARG as a right edge feature. In branching phrases, the value of EDGE | RIGHT is shared between the rightmost daughter and the mother. We further assume that ARG-ST propagates as a HEAD feature. The result of this sharing of information can be seen in ( 35), where the relevant specifications are accessible when the head-adjunct phrase is formed. At this point, we can apply a unary syntactic rule that establishes the link between the PRONARG index and the possessive NP argument, and that also "discharges" the PRONARG value.

Preverbal object clitics

The PRONARG feature is also crucial in our analysis of the preverbal object clitics presented in section 1.2. In these cases, the clitic is again suffixed to the rightmost word of a phrase, but instead of realizing an argument of that phrase (like the possessive in the previous example), a preverbal object clitic must be interpreted at the level of the whole clause.

Example (7b), repeated here as (36a), contains a preverbal object clitic attached to a PP. Example (36b)

  COMPS R 4 PRONARG 3sg         ✥ ✥ ✥ ✥ ✥ ✥ P COMPS np ru-ye np NP R 4 PRONARG 3sg miz-aš
Just as in (34) above, F pron adds a suffix to the noun miz and the corresponding index becomes the value of the PRONARG attribute. This PRONARG value could be discharged at the NP level as in the previous section, giving rise to a possessive interpretation ('on his/her table'), but instead, in this case PRONARG continues to propagate to the level of the PP, where it remains uninterpreted.

To complete the analysis of the sentences in (36), we need to modify the verb gozâšt-im 'we put' so that it can accept the suffixed PP in (37) as its complement, as opposed to the ordinary PP that we saw in earlier examples like (31) and ( 33). We propose the following lexical rule:

(38)    HEAD verb ARG-ST 1 . . . , NP i [acc], . . . ⊕ 2 PRONARG none    →   ARG-ST 1 ⊕ 2 non-aff PRONARG i   
where 2 and 2 are identical except for their PRONARG values

The effect of this rule is to add the index of an accusative NP argument to the PRONARG value of the last element of ARG-ST, which corresponds to the least oblique argument. This argument thus becomes the clitic host, and it must not itself be cliticized. The specification non-aff is compatible with either canonical realization or extraction (gap-synsem).

The change from [PRONARG none] to [PRONARG index] on the host argument ensures that the rule can only apply once: There can be only one preverbal clitic per clause. On the other hand, the original accusative NP remains on ARG-ST and its description is not further specified or modified in any way.

In the case of gozâst-im, the output of applying rule (38) to the basic lexical entry in ( 29) is as follows:

(39) gozâšt-im 'put-1PL' ❀ 'we put'         FORM F pron = gozâst-im HEAD verb ARG-ST NP 1pl , NP i [acc], PP non-aff PRONARG i        
As indicated, the morphophonological function F pron does not add a pronominal suffix to the verb if the corresponding index appears in the PRONARG value of an ARG-ST element.

The accusative NP can be further instantiated as either affixal or canonical. In the first case, it is not mapped to COMPS, and the argument is only realized once, as in (36a), which we analyze as follows:

(40) VP   COMPS R 4 PRARG none   ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ✭ ✭ ✭ ✭ ✭ ✭ ✭ ✭ ✭ pp PP COMPS R|PRARG i 3sg ✏ ✏ ✏ ✏ ✏ P COMPS 0 ru-ye 0 NP R|PRARG i 3sg miz-aš V          COMPS pp PP non-aff R|PRARG i ARG-ST NP 1pl , NP i [aff ], pp R 4 PRARG none         

gozâšt-im

On the other hand, the accusative NP in (39) can be instantiated as canonical, giving rise to clitic doubling, as in example (36b), with the following (partial) analysis:

(41) VP    COMPS np NP i [acc] R 4 PRARG none    ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ✭ ✭ ✭ ✭ ✭ ✭ ✭ ✭ ✭ ✭ pp PP COMPS R|PRARG i 3sg ✏ ✏ ✏ ✏ ✏ P COMPS 0 ru-ye 0 NP R|PRARG i 3sg miz-aš V          COMPS np , pp PP non-aff R|PRARG i ARG-ST NP 1pl , np NP i [canon], pp R 4 PRARG none          gozâšt-im
Unlike in (40), in this derivation the VP is not saturated, so it can still combine with the syntactic NP[acc] complement corresponding to the clitic -aš.

Remaining details

In this section we fill in a few remaining gaps in our formal analysis. First, we assume that verbs (and other heads) are lexically specified as having only [PRONARG none] arguments: kard-im did-1PL 'We opened the door.' + uninterpreted 2sg pronoun With (42) in place, unless the verb kard-im explicitly undergoes a derivational process like the lexical rule in (38), its complement bâz cannot host a preverbal clitic.

The fact that (38) only applies to arguments of the verb accounts for the ungrammaticality of adjunct hosts, as illustrated in ( 10)-( 11).

The various clitic co-occurrence constraints discussed in section (2.2) are handled by F pron . For example, multiply-suffixed forms like *dâd-im-aš-at in (13b) and *miz-at-aš in (22b) are simply never produced by F pron , no matter what the input. The incompatibility of clitic pronouns and ezafe can be accounted for because F pron has access to all of the right edge features of the host. Since ezafe is a phrasal affix, there must be a corresponding (boolean) feature EDGE | RIGHT | EZ that encodes its presence. F pron will only add a pronominal suffix to a host that carries the specification [-EZ] (absence of ezafe), and similarly, the morphophonological function F ez that realizes ezafe requires its host to have the feature [PRONARG none].

As the final ingredient of our formal analysis, we need to formulate a linear precedence constraint to ensure that preverbal clitics appear immediately before the verb. Although the lexical rule (38) ensures that the host is the least oblique argument, we must still prevent modifiers and other intervening elements from appearing in the syntactic realization of the clause. The following LP rule requires the clitic host (i.e. any complement with a non-empty PRONARG specification) to immediately precede the head verb:

(44) COMP-DTR PRONARG index HD-DTR V
This constraint specifies the grammatical functions of the elements involved. As a result, it correctly applies in head-complement phrases such as ( 12), but does not exclude head-filler phrases like (25).

Finally, we saw at the end of section 1.2 that some beneficiary arguments can also be realized as clitics. The definition of F pron and the formulation of the lexical rule in (38) can be modified to accommodate the examples in ( 13), with an additional constraint on clitic doubling to account for ( 14). However, a more thorough empirical investigation is required before beneficiary arguments can be fully incorporated into our formal analysis.

Further questions and discussion

Clitics in periphrastic constructions

Thus far, our analysis of object clitics only covers clauses containing a single, simple verb form. Persian also has a variety of periphrastic verb forms, with highly divergent properties. A descriptive overview and an HPSG analysis of these constructions can be found in [START_REF] Bonami | Inflectional periphrasis in Persian[END_REF]. It remains to be seen whether the present proposals can be extended in harmony with that account.

The periphrastic constructions include the passive voice and several compound tenses, and they vary with respect to the following properties: the relative order of the finite auxiliary and the lexical verb, the morphosyntactic status of the auxiliary element (word or affix), the morphological form of the lexical verb (finite or non-finite/participial), and finally (and most importantly for us) the realization and placement of object clitics. We already saw an example of a compound tense, the present perfect ("compound present" in the terminology of Bonami and Samvelian), in example (21) in section 2.2. In this tense, the auxiliary verb budan is realized as a suffix on the participle; in other words, the present perfect is not truly periphrastic. The resulting suffixed form is incompatible with further object clitic suffixation. This type of incompatibility can be integrated into the definition of F pron , which has access to the HEAD features of the verb (in particular, VFORM). Note that this restriction has no effect on the preverbal clitic in (21c), which is still correctly licensed by lexical rule (38).

The following examples illustrate the past perfect ("complex bounded past") tense, which involves a full form of the auxiliary budan, to the right of the participle. The auxiliary can host an object clitic (45a), but the participle cannot (45b). The clitic on the head verb bud-im in (45a) and the preverbal clitic in (45c) are handled correctly by our analysis. To block the realization of the preverbal clitic in (45b), we assume that the participle karde is disqualified as a clitic host in the definition of F pron (again via the HEAD | VFORM specification). We saw the effects of this morphological restriction on this same participial form in a different syntactic context in example (20b) in section 2.2. Finally, we consider the future tense, which is the only compound tense where a non-finite lexical form appears to the right of the finite auxiliary. It is also the only construction where both the auxiliary and the lexical verb can host an object clitic:

(46) a. be to [START_REF] Bonami | Inflectional periphrasis in Persian[END_REF] treat xâh-im dâd as a single inflected form. At first glance the clitic placement in (46b) seems problematic for this analysis, but in fact, since F pron has access to the internal morphological structure of this verb form (encoded in the I-FORM value), it can be defined to realize the clitic -aš either as a suffix or as an infix.

While this approach is technically feasible, there appears to be no additional motivation for allowing infixation in the morphology of Persian. For this and other reasons (e.g. word order facts not taken into account by Bonami and Samvelian), it is useful to explore alternative, syntactic analyses of the future tense. We note some parallels between this structure and impersonal modal constructions: The "downstairs" lexical verb appears in the same bare stem form as in the future tense, and it can take an object clitic in the usual way, through head suffixation (47a). The clitic in (47b) cannot be analyzed as a preverbal clitic using the lexical rule in (38), because the modal is not a complement of did. On the contrary, did is a complement of the "upstairs" modal, and so (47b) is an instance of clitic climbing, for which we adapt the argument composition analysis proposed for related phenomena in Romance [START_REF] Abeillé | The syntactic structure of French auxiliaries[END_REF]. We suggest following a similar approach for the future tense data in (46).

Cross-linguistic considerations

Similar cliticization phenomena are found in other Western Iranian languages. Sorani Kurdish, for example, also has preverbal object clitics. In fact, as the following examples from [START_REF] Bonami | Sorani kurdish person markers and the typology of agreement[END_REF] show, preverbal placement is the only possibility: Our analysis of Persian can be easily adapted to account for this data.

Pronominal clitics are of course also found in many other language families. We already mentioned French pronominal clitics in section 3. More generally, pronouns in the Romance languages exhibit many of the same phenomena observed in Persian: the existence of weak (clitic) forms and strong forms, the affixal status of clitic forms used to realize the arguments of a verb, limited mobility (e.g. clitic climbing), and clitic doubling.

There are differences: unlike in Persian, Romance object clitics generally are not also used to realize dependents within the NP, Romance exhibits proclisis in addition to enclisis, and subject pronouns can also have clitic realization in Romance. In spite of these differences, there seems to be a rich common ground for comparative studies from a formal perspective.

As discussed in section 3.1, our analysis of Persian is inspired by Miller and Sag (1997), and we hope that further work (in particular on clitics in multi-verb structures) will be able to draw on existing HPSG analyses of Romance, and also provide new insights and develop analytical tools to improve upon earlier work.

Clitic phenomena in the Slavic languages have also received attention in HPSG in recent years, and should also be taken into account within this formal comparative perspective. A particularly striking parallel can be observed in the "floating" auxiliary clitics in Polish analyzed by [START_REF] Kupść | A new HPSG approach to Polish auxiliary constructions[END_REF]. Much like Persian object clitics, these auxiliary clitics can appear either suffixed to the verb (49a), or attached to a dependent phrase to the left of the verb: The HPSG analyses proposed for Polish and Persian have very little in common in fact, primarily because auxiliaries and objects have completely different argumental properties. Nevertheless, the remaining morphosyntactic aspects of the analyses of the two languages, specifically concerning the constraints on the position of clitics within the clause, could be brought closer together.

We believe that existing analyses of clitic phenomena, such as those mentioned here, are now available in sufficient number to allow the development of a more general theory of clitics in HPSG. These efforts will provide a formal framework for typological research and guide us in the study of the many clitic phenomena, in Persian and in other languages, that await description and formal analysis.

  / for her / for her'As we can see from these examples, full pronouns basically have the same syntactic distribution as NPs, like the proper noun Maryam.

  are possible in some ditransitive constructions, but they cannot appear on the same host. The only possibility in such cases is to have one preverbal clitic immediately before the verb, and one clitic on the verb (13d).(13) a. ketâb-râ bookit to you.'

  she washed the dress and then ironed it.' Similarly, while we have seen many examples of object clitics attached to simple past tense and present tense verbs, present perfect forms do not allow this: 8 (i) dar man / tâ man inside me, until me ([-CLITIC]) (ii) *dar-am / *tâ-yam inside me, until me ([+CLITIC]) 'We have opened it.' The contrasts in (20)-(21) clearly cannot be explained phonologically. But the hosts involved do have distinct lexical representations, and so they could impose different constraints on the realization of their direct object: [±CLITIC] in the (a) examples, and [-CLITIC] in the (b) examples. Note, however, that the verb kardeim in (21b) does in fact allow a clitic object, if it is preverbal: (21) c. bâz-aš open-3SG karde-im done-1PL 'We have opened it.'

  'the hero of this novel, (who is) driven away from his homelandPP is moved away from the right edge of the relative clause, the incompatibility disappears, and the relative clause can receive the ezafe suffix (24b).

'

  If you want to open it tomorrow . . . ' c. * bâz open [

  'if we showed the books to the girl'

)

  Without this constraint, spurious object clitic pronouns, not corresponding to any argument, could be freely instantiated:

  can see him/her.'

  't you written in such a long time?' b. Dlaczego [tak długo]-ś nie pisała? c. Dlaczego-ś [tak długo] nie pisała?

  Clitics in preverbal position are sometimes ambiguous, allowing either an object clitic reading, or an adnominal clitic reading. For example, the PP in (7b) could instead be interpreted as a possessive: ru-ye [miz-aš] 'on his/her table'.Preverbal realization of object clitics is subject to various constraints. First, a single argument cannot be cliticized twice (as a preverbal clitic and as a clitic on the verb):

		[ PP ru-ye	miz]	gozâšt-im-aš
		on-EZ	table	put-1PL-3SG
		'We put it on the table.'
	b. [ PP ru-ye	miz]-aš	gozâšt-im
		on-EZ	table-3SG	put-1PL
	(8) *bâz-aš	kard-im-aš
	open-3SG	did-1PL-3SG
	(intended) 'We opened it.'
	However, as we saw for clitics on the verb in (5), a preverbal clitic can double an
	NP object (in colloquial registers):
	(9) a. dar-râ			bâz-aš	kard-im
		door-DDO	open-3SG	did-1PL
		'We opened the door.'
	b. ketâb-râ		[ PP ru-ye	miz]-aš	gozâšt-im
		book-DDO	on-EZ	table-3SG	put-1PL
		'We put the book on the table.'
	Preverbal clitics are also sensitive to the syntactic function of their host. As we
	just saw in examples (6)-(7), they can attach to another complement of the verb.
	Adjuncts, on the other hand, cannot host object clitics:
	(10) a.	[ PP dar	xiâbân]	did-im-aš
			in	street	saw-1PL-3SG
		'We saw him/her/it in the street.'
	b. * ? [ PP dar	xiâbân]-aš	did-im
			in	street-3SG	saw-1PL
	(11) a.	zud		did-im-aš
		early	saw-1PL-3SG
		'We saw him/her/it early'
	b. * zud-aš	did-im
		early-3SG	saw-1PL

  involves the same structure, but with clitic doubling. PP ru-ye miz ] -aš ❀ 'on the table' + uninterpreted 3sg pronoun PP

	(36) a. [ PP ru-ye	miz	] -aš		gozâšt-im
	on-EZ	table	-3SG	put-1PL
	'We put it on the table.'
	b. ketâb-râ	[ PP ru-ye	miz	] -aš	gozâšt-im
	book-DDO	on-EZ	table	-3SG	put-1PL
	'We put the book on the table.'
	The following figure shows the analysis of the suffixed PP complement found in
	these sentences: 14
	(37) [

† We wish to thank the participants of the HPSG seminar at Paris Diderot University, as well as the anonymous reviewers and participants of the 2010 HPSG conference. Special thanks go to Olivier Bonami, Philip Miller, Franc ¸ois Mouret, and Gert Webelhuth. This work is supported by the bilateral project "PerGram", with funding from the ANR (France) and the DGfS (Germany) [grant no. MU 2822/3-I].1 Colloquial/familiar variants are shown in parentheses. With a few exceptions, the examples in this paper adopt literary/formal pronunciation.2 In addition to familiar categories (person/number, etc.), the following abbreviations are used in glosses: DDO = the definite direct object marker râ, EZ = the ezafe linking vowel (y)e, IPF = imperfective, SBJ = subjunctive.

See fn. 8 for the forms of the subject agreement markers (e.g. -im), which are not to be confused with the object clitics under discussion here.

Example (12b) is ungrammatical given the intended interpretation (indicated by the bracketing). The sentence is acceptable, however, with a possessive interpretation of the clitic: be [doxtar-ešan] 'to their daughter'.

For the pronunciation of the clitics, see fn. 1.

See Lazard (2006, §22, §118).

Those that cannot could be assumed, within a syntactic analysis, to subcategorize for a [-CLITIC] complement. This would account for contrasts like the following:

The present perfect involves a participial form followed by an enclitic form of the auxiliary budan 'be', which we assume, following[START_REF] Bonami | Inflectional periphrasis in Persian[END_REF], to be a suffix. This auxiliary

Recall from (11) that preverbal clitics cannot attach to adverbial modifiers.

As explained below in section 3.5, we further assume that all elements on ARG-ST in this basic (underived) lexical entry carry the feature [PRONARG none].

See Bonami and Samvelian (2009) for a treatment of Persian verbal morphology using Paradigm Function Morphology within HPSG.

As it stands, our formulation implies free variation between the presence and absence of the suffix. In reality, the stylistic effects associated with clitic doubling would need to be incorporated

We leave aside the analysis of the ezafe suffix in this example. We return briefly to the issue of ezafe in section 3.5, but for a full discussion, see[START_REF] Samvelian | A phrasal affix analysis of the Persian Ezafe[END_REF].

Ru-ye is in fact a grammaticalized nominal element with the ezafe suffix, but here we analyze it simply as a preposition.