Adelina Moura
email: adelina8@gmail.com

Ana Amélia Carvalho

Mobile Learning: Using SMS in Educational Contexts

Keywords: Mobile learning, SMS, mobile phones, mobile contents, language learning

The Short Message Service (SMS) technology is one of the most powerful mobile technologies in current usage. Most students own a mobile phone with free SMS which can be used for learning. In this paper we explain how we used SMS for teaching and learning languages (both native and foreign). The conducted experiment presented a range of opportunities for integrating text into teaching and learning strategies and for demystifying the use of SMS in educational contexts. Via SMS technology we can deliver several learning activities to students easily and immediately. The research findings showed that students had positive perceptions about the experiment and SMS use for learning improvement and the use of their own mobile phone as a learning tool. All groups showed interest in receiving educational content via SMS. Some students greatly improved their language learning performance.

Introduction

Never before in the history of education, has a technology been so rapidly adopted as mobile technologies. The evolution of wireless communication has created a new educational paradigm called mobile learning (m-learning). This includes the use of mobile devices (phone, PDA, pocket PC and media players like the iPod) for educational purposes [START_REF] Lominé | M-learning: texting (SMS) as a teaching & learning tool in higher arts education[END_REF]. Mobile learning experiences can take many forms and have different objectives. The goal is not to challenge or replace other forms of interaction, it is a complementary methodology that can support, enrich and enhance the learning experience.

Statistics show that more than 3 billion people around the world own a mobile phone. The penetration of mobile devices into many European countries exceeds 90% and younger generations seem to be the most dependent on this device for communication [START_REF] Traxler | Case studies: Introduction and overview[END_REF]. However, according to Schick [START_REF] Schick | The mobile lifestyle: How the fusion of the mobile and the Internet have changed the way we live, learn, and play[END_REF], most people with mobile phones only use their basic functions, such as voice communication and SMS.

SMS technology is a reliable communication system and popular among mobile phone users. It has become a trend as a means of communication throughout the world, even in less developed countries. It has been considered by several authors [START_REF] Lominé | M-learning: texting (SMS) as a teaching & learning tool in higher arts education[END_REF], [START_REF] Traxler | Case studies: Introduction and overview[END_REF], [START_REF] Kukulska-Hulme | An Overview of Mobile Assisted Language Learning: from content delivery to supported collaboration and interaction[END_REF] as an appropriate tool for education.

Several studies, such as [START_REF] Bollen | SMS-based Discussions -Technology enhanced collaboration for a literature course[END_REF], [START_REF] Levy | Learning Italian via mobile SMS[END_REF], [START_REF] Markett | Using short message service to encourage interactivity in the classroom[END_REF], [START_REF] Naismith | Using text messaging to support administrative communication in higher education[END_REF], [START_REF] Song | SMS enhanced vocabulary learning for mobile audiences[END_REF], [START_REF] Nix | Mobile learning/SMS (Short Messaging System) academic administration kit[END_REF], [START_REF] Scornavacca | Developing a SMS-based classroom interaction system[END_REF], [START_REF] So | The development of a SMS-based teaching and learning system[END_REF], [START_REF] Moura | Mobile learning: two experiments on teaching and learning with mobile phones[END_REF] suggest the integration of SMS by educational institutions to maintain contact with students in teaching and learning contexts. In this paper we present a learning environment supported by SMS for learning languages (Portuguese as mother tongue, and French as foreign language). We designed this study based on a few teaching and learning projects by SMS described above.

Mobile Learning: a New Concept in Education

The use of mobile phones and other mobile devices is having an impact on where learning takes place in many areas and contexts, including language learning [START_REF] Kukulska-Hulme | Will mobile learning change language learning?[END_REF]. Mobile technologies do not depend on a fixed location and are enable users to learn or access information. This helps maximise significant changes in teaching and learning practices.

A number of publications over the last decade [START_REF] Moura | Mobile learning: two experiments on teaching and learning with mobile phones[END_REF], [START_REF] Kukulska-Hulme | Will mobile learning change language learning?[END_REF], [START_REF] Kukulska-Hulme | Mobile Learning: A Handbook for Educators and Trainers[END_REF], [START_REF] Faux | Handhelds: learning with handheld technologies[END_REF], [START_REF] Sharples | Big issues in mobile learning[END_REF] show that mobile learning is a growing field with interest in many areas, particularly education. Although there is no consensus on the definition of mobile learning, because it is a rapidly evolving field and due to the ambiguity of the term mobile [START_REF] Kukulska-Hulme | Will mobile learning change language learning?[END_REF], experiments and pilot studies have been conducted in this field in recent years. While the term learning is undoubted, the mobile concept can refer to the mobility of the learner as well as the mobility of content. In this sense, mobility should not only be understood in terms of spatial movement, but also in terms of processing time and without physical boundaries, thus widening the horizons of learning and information access.

Despite the fact that m-learning focuses heavily on mobility, the most important aspect is its educational effect. Through appropriate technology, learners can participate in activities directly related to their needs and contexts (just-in-time learning). This forces educators to rethink teaching and learning processes.

SMS: a Technology for Learning in the Digital Age

The adoption of SMS as an educational resource has become popular in recent years [START_REF] Goh | To TxT or not to TxT: That's the puzzle[END_REF]. SMS is a technology that allows mobile phones to send and receive short text messages. The original size of the messages was 160 characters, but the latest mobile phone models support can receipt of messages with up to 612 characters.

Recently there has been much interest from academic institutions regarding the use of mobile technologies to support teaching and learning. The evolution of mobile devices, although not designed specifically for education, is increasing opportunities in education, with the potential for mobile learning contexts [START_REF] So | The development of a SMS-based teaching and learning system[END_REF]. One example with great educational potential is sending an SMS via mobile phone that has great educational potential [START_REF] Traxler | Case studies: Introduction and overview[END_REF], thus meeting the needs of society in the digital age. Over the last decade, various SMS-based projects have been created to support the teaching and learning process, particularly in language learning.

SMS-Based Projects in Educational Institutions

Several studies and experiments regarding the use of SMS in different educational contexts have taken place during recent years. The following examples constitute the basis for this project.

An experiment was conducted by Naismith [START_REF] Naismith | Using text messaging to support administrative communication in higher education[END_REF] in a university context based on sending SMS messages to students about the cancellation of classes, information, reminders, and academic pursuits. This administrative communication with students was positive and staff expected to extend this project to other institutional sectors. In another study, a tool was implemented for communication and discussion [START_REF] Bollen | SMS-based Discussions -Technology enhanced collaboration for a literature course[END_REF] based on sending SMS messages via PDA that aimed to initiate discussions and collaborative work. Results showed that the technology improved collaborative work in literature courses. A study conducted by Song [START_REF] Song | SMS enhanced vocabulary learning for mobile audiences[END_REF] explored the role of SMS in learning the vocabulary of English as a foreign language. This involved ten participants and the final results showed a significant improvement in the students' performance and their attitude towards the use of SMS in learning vocabulary. Another experiment conducted by Nix et al. [START_REF] Nix | Mobile learning/SMS (Short Messaging System) academic administration kit[END_REF] showed the success achieved by using SMS messages to reduce early abandonment of courses by university students. It seems that sending SMS messages to students identified as being at risk was successful in helping retain students in the system.

The TXT-2-LRN system, developed by Scornavacca et al. [START_REF] Scornavacca | Developing a SMS-based classroom interaction system[END_REF], based on SMS allows the interaction between students and teachers in the classroom. Students can send questions and comments to the teacher's computer via SMS. The project PLS TXT UR Thoughts, conducted by Markett et al. [START_REF] Markett | Using short message service to encourage interactivity in the classroom[END_REF], allowed students to send SMS in real time through their personal mobile phones during class and online after school and encouraged interactivity with the classroom.

Other authors, such as Goh & Hooper [START_REF] Goh | To TxT or not to TxT: That's the puzzle[END_REF], explored the feasibility of using SMS in mobile phones to promote learning through the use of crossword SMS environments in the classroom, with positive participation.

SMS and m-Learning

Since mobile phones and SMS communication are so popular outside school we only need to combine these two technologies, import them, and adopt them in educational contexts. SMS is a part of m-learning (fig. 1). In initial conversations with students about using SMS in an educational environment, the reaction is one of unfamiliarity, but this awkwardness will diminish following contact with activities and realising the benefits of using it. What is important is that we ensure the educational value of this resource by delivering useful content and creating teaching strategies for students. Mobile phones have become a "high tech" device because they have a camera, Internet access, and the ability to install a large number of applications. SMS is considered "low tech", when compared to the use of sound, images and videos which will make m-learning more creative and dynamic, particularly in language learning, but it should not be neglected. In addition to mobility SMS presents other advantages [START_REF] Lominé | M-learning: texting (SMS) as a teaching & learning tool in higher arts education[END_REF]: i) it forces users to express themselves concisely;

ii) the written text uses very little memory thus keeping costs to a minimum;

iii) using it does not require technical learning.

The Use of SMS for Learning Languages

Several authors [START_REF] Kukulska-Hulme | An Overview of Mobile Assisted Language Learning: from content delivery to supported collaboration and interaction[END_REF], [START_REF] Levy | Learning Italian via mobile SMS[END_REF], [START_REF] Song | SMS enhanced vocabulary learning for mobile audiences[END_REF], [START_REF] Pincas | Using mobile phone support for use of Greek during the Olympic games 2004[END_REF] consider SMS technology to be suitable for language learning. The possibility for students to access useful information anywhere and anytime is a potential of SMS technology [START_REF] Lominé | M-learning: texting (SMS) as a teaching & learning tool in higher arts education[END_REF]. Mobile devices, particularly mobile phones, are ideal for the promotion of learning by sending students SMS learning units in hours and days planned to optimize their free time.

A study was conducted based on learning Italian via SMS in an Australian university [START_REF] Levy | Learning Italian via mobile SMS[END_REF]. Students were sent new words, definitions and examples of words in context by SMS. Students could read these materials in between classes. The final remarks presented positive results.

Another study, conducted by Lu [START_REF] Lu | Effectiveness of vocabulary learning via mobile phone[END_REF], reported the use of SMS for learning English as a foreign language in Taiwan. Messages containing vocabulary were sent to students during their lessons. They read the messages regardless of location and time. Students showed a preference for learning through the mobile phone rather than the computer because mobiles are more convenient than PCs in many situations.

In Japan, Thornton & Houser [START_REF] Thornton | Using mobile phones in English Education in Japan[END_REF] conducted a study using SMS and e-mail to teach English vocabulary. Teachers introduced five words weekly as well as messages sent with mini-lessons three times a day via SMS. The lessons included learning simple terms, some explanatory words, and a review of the words learned. This provided a positive result in learning new English words.

An experiment was carried out with SMS to support the learning of technical vocabulary [START_REF] Cavus | M-Learning: An experiment in using SMS to support learning new English language words[END_REF]. Spaced repetitions of the same message were sent on different days through an SMS-based system called MOLT (mobile learning tool) and developed by the authors. Results showed that students enjoyed the experiment and learned new words with the help of their mobile phones.

Using SMS for Language Learning: infrastructure

In order to develop the learning-via-SMS experiment we started with ideas presented by some authors [START_REF] Traxler | Case studies: Introduction and overview[END_REF], [START_REF] Kukulska-Hulme | An Overview of Mobile Assisted Language Learning: from content delivery to supported collaboration and interaction[END_REF] together with the fact that most students always have their mobile phone with them and use it mainly to communicate via SMS. Three objectives guided this project: i) to integrate the phone as a learning tool; ii)

to explore a learning environment for SMS to promote language learning inside and outside the school; iii)

to encourage students to participate spontaneously and independently in learning outside of the classroom. This experience of learning via SMS allowed individual or group SMS messages to be sent. Student phone numbers were stored in a computer database which allowed teachers to send quick messages to each individual student or to the whole group.

The model was based on the Vodafone "SMS by Mail" system in order to provide students with curricular content units and other information via SMS. The SMS messages were written in Outlook on the teacher's computer and sent via the SMS by Mail system to student's mobile phones, to be read, stored and responded. The students in turn sent the replies to the teacher's mobile phone (fig. 2).

Study Description

The reported study was an exploratory one and was part of a larger study on the use of mobile phones as learning tools. We used a qualitative research methodology, with multiple cases using new educational technologies [START_REF] Yin | Case study research: Design and methods[END_REF].

Once we had verified that all students owned a mobile phone, and that the majority had contracts with the same provider, with free SMS between SIM cards on the same network, we felt we had met the conditions for developing a learning environment by SMS in Portuguese and French classes. For about six weeks, text messages were sent daily, three-times a day, in a schedule agreed upon with students. The activities were divided into three scenarios: i) units of learning to read and store on mobiles not requiring student response; ii) activities that ask questions or demand tasks; iii) activities including collaborative tasks (table 1).

The activities were spread over the duration of the experiment. Approximately one hundred messages were sent and more than nine hundred received.

Data Collection

Data collection was conducted through two questionnaires, individual interviews, and focus groups. The opinion questionnaire was answered at the end of the experiment and aimed to collect information about students' perceptions regarding the activities carried out by SMS. The questionnaire used closed questions (dual or multiplechoice), open-ended questions and a Likert scale with five levels (strongly disagree to strongly agree). The individual interviews and focus groups were conducted at the end of the study.

Sample Characterization

This study took place in the school year 2008/2009, both in Escola Secundária Carlos Amarante and Escola Profissional de Braga, and was attended by four groups (table 2), aged 15 to 20 in groups A, B, and C. Those aged between 22 and 56 composed group D. A total of 68 students participated in this study, 46% female and 54% male. Participants of Group B were from a private vocational school and the other groups were from a public high school. Participants from group D were adult students who attended evening classes.

Data Analysis

Data obtained from the questionnaire focused on two aspects: i) the educational value of learning activities by SMS; ii) the evaluation of learning activities by SMS. Data collected through individual interviews and focus groups helped confirm the data obtained in the questionnaire, and gave the data reliability.

Educational Value of Learning Activities by SMS

We asked participants about the educational value of the daily "Word of the Day", reading activities and all the other learning activities by SMS such as: stories and fables which motivated the students to read (table 3). The majority of respondents in groups B (56%) and C (78%) and all those in group D found that daily reading through stories and fables motivated reading, while most of those in group A (59%) responded negatively. Group A is composed of males; most of them (67%) did not like studying or reading. However, 41% of them found that reading through SMS motivated them to read. This strategy may have educational potential, with regards to the motivation for reading in individuals with this profile. All participants in groups B and D as well as the majority of respondents in groups A (78%) and C (94%) reported that the activity "Word of the Day" helped to enrich their vocabulary. For all the activities sent by SMS, all those in group D and the majority of other respondents (67% A, B, 89%, C 94%) said it motivated them to learn.

Evaluation of the SMS Learning Experience

To evaluate the participants' reactions in relation to this learning environment by SMS, we questioned students about: i) the satisfaction or dissatisfaction of scenario 1 learning units; ii) the degree of difficulty of scenario 2 learning units.

Students' Reactions to the Scenario 1 Learning Units

We questioned participants about their satisfaction or dissatisfaction in receiving learning units to read and store: "Word of the Day" for the construction of a dictionary on their mobile phone, several course contents to store on the device, and thoughts for reflection (table 4). The majority of respondents in group A (56%), B (67%) and C (78%) and all those in group D liked the activity "Word of the day". These results are consistent with those obtained in other studies [START_REF] Levy | Learning Italian via mobile SMS[END_REF].

All respondents from group D and the majority of respondents from groups B (72%) and C (78%) liked to receive the curricular contents, but for the majority of respondents in group A (56%), this was irrelevant. Two students responded negatively.

Most participants in groups A (52%), B (89%) and C (78%) and all the individuals in group D liked receiving the "Thoughts".

Degree of Difficulty of Scenario 2 Learning Units

The activities that asked students for one reply were intended to promote the reading and understanding of the different information units that were sent. In order to promote interaction between students and teachers, these activities were questions that students had to answer, so we polled students about the degree of difficulty of each activity (table 5). The multiple choice activities with curricular content were easy for most participants in groups A (55%) and C (61%), and moderate for the majority of respondents in groups B (75%) and D (60%). The game "Who wants to be a millionaire?", Proverbs and Riddles were considered moderate by the majority of respondents from all groups. A daily reading based on fables followed by the identification of the moral of the story was considered moderate by less than half in group A (44%), half of respondents in group C, 55% in group B and 60% in group D. The fact that these activities had some degree of difficulty challenged the students to build knowledge. Many of them asked family members to look for other resources (Internet, books, etc.) to find the correct response.

Reaction to all Activities Sent by SMS

We asked students whether or not they liked all activities sent by SMS (table 6). All respondents in group D and the majority of participants in groups A (93%), B (94%) and C (94%) enjoyed all activities sent by SMS. The same satisfaction was confirmed by data collected through individual interviews and focus groups. All students interviewed stated that they enjoyed this type of learning. In individual interviews, students said they had improved their learning: "The SMS helped me learn the foreign language ... and I assimilated better the information that was sent"¸ "I liked the SMS ... so much content ... it helped a lot"; "The SMS sent by the teacher ... in leisure time I copied it into my notebook and I learned better".

Students who carried out the collaborative activities by SMS to create a micro story through SMS, face-to-face and at adistance said they liked it because it was a different way of working in pairs. It helped them interact and solve problems.

In this paper we have presented a study about the development of learning languages with the support of SMS. Despite the size limitations of SMS messages, they seemed to be, in some scenarios, such as language learning, a quick and effective way of providing students with small learning units. We believe that this kind of practice can provide students and teachers with innovative learning experiences by taking advantage of the ubiquitous nature of mobile phones, the infrastructure of the SMS, and the ability to send relevant information. As noted by participants in the study, the contents were condensed and they facilitated reading and its assimilation. Receiving information broken into small units seemed to be easily understood by students [START_REF] Habitzel | Microlearning: Emerging concepts, practices and technologies after e-learning[END_REF]. In general, students liked the activities, recognised them as stimulants and felt that they promoted learning.

We must not be dazzled by technology. The teaching strategies and methods performed with technology are of utmost importance [START_REF] Chisholm | Micro-Learning in the Lifelong Learning Context[END_REF]. It is important that teachers promote interaction in the classroom because it has been shown that it improves learning [START_REF] Markett | Using short message service to encourage interactivity in the classroom[END_REF], and mobile technologies enable interaction inside and outside the classroom.

The characteristics of mobile devices allow learners to construct knowledge in different contexts and to access information anywhere, anytime. One advantage of this educational concept is the possibility of interaction (teacher-student-student). The portability of these devices allows users to take notes or collect data on an ongoing basis and at any moment. Directly on the device they can write a text, capture an image, make a video or record voice. The mobile phone is a collaborative tool that allows multiple students to work together on a task even when in remote locations, and it also promotes the engagement of learners.

Mobile devices are becoming increasingly ubiquitous, enabling their use in an educational context. The ubiquity of mobile devices will make m-learning an important way of providing education and training in the future.

Fig 1 .

 1 Fig 1. SMS a part of m-learning (adapted from Lominé & Buckhingham [1])

Fig 2 .

 2 Fig 2. SMS learning infrastructure

Table 1 .

 1 Three scenarios of activities by SMS

	Scenario 1	Scenario 2	Scenario 3
	Learning unities to read and	Requesting Activities	Collaborative Activities
	store
	-Thoughts	-Quizzes	-Writing a collaborative
	-Curricular Contents	-"Who Wants to Be a	micro story at a distance
	-Word of the Day	Millionaire"	-Writing a collaborative
	(Dictionary)	-Read Daily -(fables)	micro story face-to-face
		-Riddles
		-Proverbs

Table 2 .

 2 Participant's profile

	Groups	Group A	Group B	Group C	Group D
			(n=27)		(n=18)	(n=18)		(n=5)
	Sex	f	%	f	%	f	%	f	%
	Female	0	0	18	100	10	56	3	60
	Male	27	100	0	0	8	44	2	40

Table 3 .

 3 Educational value of learning activities by SMS

	Items		Group A	Group B	Group C	Group D
		Answer	(n=27)	(n=18)	(n=18)	(n=5)
			f	%	f	%	f	%	f	%
	Receiving stories and fables	Yes	11 4 1	10	56	14	78	5	100
	motivated reading	No	16	59	8	44	4	22	0	0
	Receiving word definitions	Yes	21	78	18 100	17	94	5	100
	helped to enrich vocabulary	No	6	22	0	0	1	6	0	0
	The set of all activities	Yes	18	67	16	89	17	94	5	100
	encouraged learning	No	9	33	2	11	1	6	0	0

Table 4 .

 4 Students' reactions to the scenario 1 learning units

	Items		Group A	Group B	Group C	Group D
			(n=27)	(n=18)	(n=18)		(n=5)
			f	%	f	%	f	%	f	%
	Word of the Day (dictionary)	Positive Indifferent Negative	14 11 0	56 44 0	12 6 0	67 33 0	14 4 0	78 22 0	5 0 0	100 0 0
		Positive	10	37	13	72	14	78	5	100
	Curricular contents	Indifferent	15	56	5	28	4	22	0	0
		Negative	2	7	0	0	0	0	0	0
		Positive	14	52	16	89	14	78	5	100
	Thoughts	Indifferent	12	44	2	11	4	22	0	0
		Negative	1	4	0	0	0	0	0	0

Table 5 .

 5 Degree of difficulty of the scenario 2 learning units

	Items		Group A	Group B	Group C	Group D
		Answers	(n=27)	(n=18)	(n=18)	(n=5)
			f	%	f	%	f	%	f	%
	Multiple Choice (curricular content)	Easy Moderate Demanding	15 11 1	55 41 4	5 13 0	25 75 0	11 7 0	61 39 0	2 3 0	40 60 0

Table 6 .

 6 Reaction to all activities sent by SMS

	Did you like the activities by	Group A	Group B	Group C	Group D
	SMS?	(n=27)	(n=18)	(n=18)		(n=5)
		f	%	f	%	f	%	f	%
	Yes	25	93	17	94	17	94	5	100
	No	2	7	1	6	1	6	0	0

Acknowledgments. Thanks to Vodafone for sponsoring the SMS by Mail service used in this study, and teacher mobile devices (mobile phone and netbook).

This research is in part funded by CIEd, University of Minho.


Luc Trouche

Webbing and orchestration Two interrelated views on digital tools in mathematics education

Webbing and orchestration. Two interrelated views on digital tools in mathematics education

Luc Trouche,

Introduction

Since their introduction in the 80s of the previous century, the integration of digital tools in mathematics education is considered both promising and problematic. On the one hand, the potential of digital tools is widely recognized. New technologies are expected to open up new horizons of explorative and productive mathematics education, in which opportunities for experiencing dynamics, for visualizing concepts, and for integrating different representations and resources provide new means of rich and meaningful teaching and learning activities (e.g., see NCTM, 2008;[START_REF] Pea | Cognitive technologies for mathematics education[END_REF]. On the other hand, the integration of digital tools is considered as problematic in the sense that their availability questions the goals of mathematics education as well as current teaching practices [START_REF] Lagrange | Technology and Mathematics Education: a Multidimensional Study of the Evolution of Research and Innovation[END_REF]. The latter type of question has not yet been answered in a satisfying way, which may explain the limited integration of digital tools in mathematics education in spite of earlier high expectations.

In order to address the problematic character of the integration of digital tools, educational research was needed that would go beyond enthusiastic reports from first adopters who engaged in small-scale design experiments, and that would be firmly based on theoretical foundations. For some time, such foundations were lacking; in the 90s, however, two important theoretical views emerged: the notion of webbing and the instrumental approach to tool use. Building on ideas on scaffolding, the notion of webbing was introduced by [START_REF] Noss | Windows on Mathematical Meanings. Learning Cultures and Computers[END_REF]. Noss and Hoyles were inspired by the work of Papert (e.g., see [START_REF] Papert | Mindstorms : Children, Computers and Powerful Ideas[END_REF] and elaborated his views for the context of using digital learning environments called microworlds for mathematics education. The LOGO programming language served as a paradigmatic environment. In the meantime, the instrumental approach emerged in France (e.g., see [START_REF] Guin | The complex process of converting tools into mathematical Instruments. The case of calculators[END_REF]. This approach, which has its roots in cognitive ergonomics [START_REF] Vérillon | Cognition and artefacts: A contribution to the study of thought in relation to instrument activity[END_REF] and the anthropological theory of didactics [START_REF] Chevallard | L'analyse des pratiques enseignantes en théorie anthropologique du didactique[END_REF], highlights the importance of a meaningful relationship between a tool and its user for carrying out a specific task. To stress the importance of the teacher in the students' process of establishing such a relationship, the notion of instrumental orchestration was developed [START_REF] Trouche | Managing the Complexity of Human :Machine Interactions in Computerized Learning Environments: Guiding Students' Command process Through Instrumental Orchestrations[END_REF].

Initially, the notions of webbing and instrumental orchestration seemed to be rather disconnected, also because of their different cultural and theoretical backgrounds. Whereas the webbing metaphor was oriented towards students' productive and expressive activities, the focus of the instrumental approach was more on the appropriation of given tools for mathematical learning. From the beginning, however, the two 'schools' not only made use of metaphors, but also shared an interest in using digital tools for learning and both highlighted the fact that tools are not just neutral but do impact on student behaviour and on student learning: Tools matter: they stand between the user and the phenomenon to be modelled, and shape activity structures. (Hoyles & Noss, 2003, p. 341) As a consequence, the two views gradually came into contact with each other, and to a certain extent informed each other's further development. It is this mutual influence and development that is at the heart of this article's interest. The central theme of this paper, therefore, is (1) to investigate the ways in which these theoretical notions 'travelled through time', each on its own and in relation to each other, and (2) to assess their impact on future research and teaching. Not claiming a comparison and contrasting that characterises a networking of theories study (e.g., see [START_REF] Prediger | Networking strategies and methods for connecting theoretical approaches: first steps towards a conceptual framework[END_REF][START_REF] Drijvers | One episode, two lenses; A reflective analysis of student learning with computer algebra from instrumental and onto-semiotic perspectives[END_REF], we want to describe the distinct and joint journeys of the two perspectives at stake. To do so, the paper follows a more or less chronological line. In section 2, the two 'main actors' are described as they emerged by the end of the previous century. Next, section 3 identifies some differences between the two views, as they became apparent in a symposium in 2003. A further rethinking of the two concepts took place in the frame of the 17 th ICMI study (Hoyled and Lagrange, 2010), particularly with respect to the idea of connectivity. As a final development, we focus in section 5 on teachers and teaching, and on the ways the theoretical frameworks inform teachers' professional development. A recent ZDM issue on re-sourcing teacher work, edited by Pepin, [START_REF] Gueudet | Collective work with resources: an essential dimension for teacher documentation[END_REF] serves as a benchmark here.

The two main actors: webbing and orchestration

In this section we briefly describe the main characteristics of the two main 'actors' in this paper: the notions of webbing and of instrumental orchestration.

Webbing

Noss and Hoyles introduced the notion of webbing in their 1996 book 'Windows on mathematical meanings'. This book was to a large extent inspired by the work of Papert and other on constructionism (e.g., see [START_REF] Papert | Mindstorms : Children, Computers and Powerful Ideas[END_REF][START_REF] Papert | Mindstorms : Children, Computers and Powerful Ideas[END_REF][START_REF] Papert | Situating Constructionism[END_REF]. As a point of departure, the authors see learning as the construction of a web of connections of mathematical ideas, such as connections between classes of problems, between mathematical objects and relationships, or between 'real' entities and personal situation-specific experiences. These connections are captured in intellectual structures, which are individual and can be (re)constructed by students not only through the scaffolding by a teacher but also by themselves through the use of digital environments.

The idea of webbing is a metaphor for this process of building and using such structures. In industry, webbing refers to flexible woven material consisting of a network of natural or artificial fibres, and clearly the reference to flexibility and the interwoven character of the structure fits well Noss and Hoyles' view on learning. The authors themselves describe webbing as follows.

Like the web of mathematical ideas, the Web (we will use a capital to denote the electronic network), is too complex to understand globally -but local connections are relatively accessible. At the same time, one way -perhaps the only way -to gain an overview of the Web is to develop for oneself a local collection of familiar connections, and build from there outwards along lines of one's own interests and obsessions. The idea of webbing is meant to convey the presence of a structure that learners can draw upon and reconstruct for support -in ways that they choose as appropriate for their struggle to construct meaning for some mathematics. (Noss & Hoyles, 1996, p. 108) In this sense, webbing is considered a fundamental motor for the construction of mathematical meaning, and a step towards situated abstraction. The resulting structures form a support system, a system that the learner has access to and is in control of. Digital environments provide excellent opportunities to build and use such webbing structures, which are shaped by and within the medium. The word 'webbing' refers to both the process of constructing and using connecting structures, and to the resulting structures themselves. As illustrative examples, Noss and Hoyles refer to student observations that they label as flagging, adjusting, sketching, and patterning.

When addressing webbing in the sense of Noss and Hoyles, we should be aware that nowadays, we may have strong associations with the omnipresent Internet, which in the 1990s was only present in its very early and rudimental forms. Some care may be needed to frame the notion of webbing in its current era.

Instrumental orchestration

The instrumental approach to mathematics education emerged in the French context of didacatical engineering, the theory of didactical situations and the anthropological theory of didactics. It initially mainly dealt with complex technological environments such as CASs that were provided to students and teachers, but that were not at all designed for educational purposes (e.g., see [START_REF] Guin | The complex process of converting tools into mathematical Instruments. The case of calculators[END_REF][START_REF] Artigue | Learning Mathematics in a CAS Environment: The Genesis of a Reflection about Instrumentation and the Dialectics between Technical and Conceptual Work[END_REF]. At its start, it took three essential ideas from cognitive ergonomics [START_REF] Vérillon | Cognition and artefacts: A contribution to the study of thought in relation to instrument activity[END_REF]:

1. The distinction between an artefact and an instrument: an artefact is a material or abstract object, a product of human activity, and is used for performing a type of task. Examples are calculators, and algorithms for solving quadratic equations. These artefacts are given to a subject; an instrument is what the subject builds from the artefacts; 2. The acknowledgement that the process of appropriating an artefact and building an instrument is a complex one. This process is called instrumental genesis, in which a new entity is given birth. This new instrument is composed of the part of the artefact really mobilized and of a scheme, i.e., the structured cognitive organisation of the activity for carrying out the task; 3. The comprehension that instrumental genesis is not a single process, but fundamentally involves two interrelated movements, namely instrumentation (in short: the artefact engraving its mark on the user activity), and instrumentalisation (in short: the user engraving its mark on the artefact).

The proper contribution of the instrumental approach to an understanding of the complexity of tool use in mathematics education was to consider a scheme as a source for building mathematical knowledge. For example, Drijvers (2002, p. 226) describes the emergence of the scheme Isolate-Substitute-Solve for solving a system of two equations (x + y = 31 and x 2 + y 2 = 25 2 ) with two unknowns in a symbolic calculator environment (Figure 1). Underlying this scheme is the extending conceptualisation of "what solving an equation is", from "finding a numerical value for an unknown", to "expressing one unknown as a function of another". The meaning of the word "instrumental" in the instrumental approach is quite different from [START_REF] Skemp | Relational Understanding and Instrumental Understanding[END_REF] description of the relational -instrumental understanding dialectic. In the latter view, instrumental understanding is "applying rules without reasons". In the instrumental approach, developing techniques is creating reasons: instrumentation and conceptualisation are deeply intertwined. This mutual influence leads to taking into account the responsibility of the teacher, and more generally, of the educational institution, for steering students' instrumental geneses. This awareness leads to the notion of instrumental orchestrations, that Trouche (2004, p. 296) defines as follows.

An instrumental orchestration is defined by didactic configurations (i.e., the layout of the artefacts available in the environment, with one layout for each stage of the mathematical treatment) and by exploitation modes of these configurations.

The sherpa-student configuration depicted in Figure 2 can be considered as paradigmatic of the notion of orchestration. The didactical configuration consists of an organisation of the classroom space, in which each student has his own handheld device, that can be connected to a projection device. All students are seated so that they can see the projection. The exploitation mode comes down to the teacher inviting one student to connect his device and to show his work or to carry out tasks suggested by the teacher. This gives means to the teacher to follow and monitor students' instrumented activity, related to the demands of the mathematical task at stake. The sherpa-student configuration (Trouche, 2004, p. 298) The idea of orchestration constitutes a powerful metaphor that also appears in other theoretical frames.

For example, [START_REF] Mariotti | Resources for the teacher from a semiotic mediation perspective[END_REF] include the notion of orchestration in their semiotic mediation approach in the sense of "developing shared meanings, having an explicit formulation, decontextualized from the artefact use, recognizable and acceptable by the mathematicians' community". The work by Stein and colleagues ( 2008) focuses at the orchestration of classroom discussions, for "helping teachers move beyond show and tell". In this case, orchestration remains a global perspective and the authors mainly highlight the general conditions for such discussions to happen: they make a plea for designing learning environments "so that students are "authorized" to solve mathematical problems for themselves, are publicly credited as the "authors" of their ideas, and develop into local "authorities" in the discipline" (Stein et al., 2008, p. 332). [START_REF] Dillenbourg | Technology for classroom orchestration[END_REF] also use the metaphor of orchestration, and propose a musical notation for the sequence of different configurations (individual, group, class, et cetera) aiming to foster student activity (Figure 3). [START_REF] Hähkiöniemi | Teacher's reflections on experimenting with technology-enriched inquiry-based mathematics teaching with a preplanned teaching unit[END_REF] suggests that teachers need support to develop an appropriate repertoire of orchestrations. The notion of instrumental orchestration as proposed by [START_REF] Trouche | Managing the Complexity of Human :Machine Interactions in Computerized Learning Environments: Guiding Students' Command process Through Instrumental Orchestrations[END_REF][START_REF] Trouche | Construction et conduite des instruments dans les apprentissages mathématiques : nécessité des orchestrations[END_REF] in mathematics education applies not only to the episodes of discussions and seems to be more precise, aiming to define the management of both space and time of a learning environment, according to the different stages of the task to be carried out.

Webbing as a model of internal students' cognitive functioning on the one hand, and instrumental orchestration as a model of guiding students' instrumental genesis on the other, seem to be at two different levels of mathematics education interests. However, these two concepts have come to meet and to engage dialogue on the occasion of the third CAME1 symposium, which will be discussed in the next section.

Differentiating the concepts of webbing and orchestration

The CAME symposium, and the theme Mind and Machine in particular, constituted a fruitful context for discussing the concepts of webbing and orchestration. In a presentation by Trouche and a reaction by Hoyles 2 addressed the approaches bearing respectively the concepts of webbing and orchestration. These two contributions share essential starting points, such as (1) recognizing the "underestimation of the complexity of instrumentation processes" (Hoyles et al., 2004, p. 311), ( 2) evidencing "a failure to theorize adequately the complexity of supporting learners to develop a fluent and effective relationship with technology in the classroom" (ibidem, p. 311), and (3) underlining the fact that "the marginalisation of technology by educational institutions has also turned our attention to the need for a more precise analysis of the role of the teacher in these new and changing didactical contexts" (ibidem, p. 313). This being said, the two papers reveal three important differentiating nuances.

The true nature of mathematical conceptualisation

In the webbing approach, conceptualisation appears as a coordination process, "the process by which the student infers meaning by coordinating the structure of the learning system (including the knowledge to be learned, the learning resources available, prior student knowledge and experience and constructing their own scaffolds by interaction and feedback)" (Hoyles, Noss, & Kent, 2004, p. 319).

In the instrumental orchestration approach, conceptualisation appears as a command process, characterized by the conscious attitude to consider, with sufficient objectivity, all the information immediately available not only from the calculator, but also from other sources and to seek mathematical consistency between them [START_REF] Guin | The complex process of converting tools into mathematical Instruments. The case of calculators[END_REF]. "Very sophisticated artefacts such as the artefacts available in a computerized learning environment give birth to a set of instruments. The articulation of this set demands from the subject a strong command process. One of the key elements for a successful integration of these artefacts into a learning environment is the institutional and social assistance to this individual command process. Instrumental orchestrations constitute an answer to this necessity." (Trouche, 2004, p. 304). It seems that there is a kind of intended internalization from an instrumental orchestration, seen as an external process of monitoring students' instruments by the teacher, to an internal orchestration 3 , seen as a process of self-monitoring the individual and personal instruments by a student.

Coordination and control are certainly two facets of mathematical activity, particularly in technological rich environment, and the two approaches seem to privilege, each, one of these facets.

The role of interactions between learners

Hoyles et al. clearly situate this nuance: "Perhaps the different unfolding histories of our respective research efforts -including the choice of technologies to study, has resulted in differences in emphasis between us rather than in core perspective, most notably regarding the weight we accord to the role of interactions among learners […] (ibidem, p. 317)". Here seems to emerge a kind of intended externalization, from the webbing as an internal process ( § 1.1) to a webbing as connections between learners, with mathematical knowledge emerging from these connections. In this approach, social aspects seem to relate mainly to interactions between pupils, while, for the instrumental approach, social aspects are in many cases orchestrated by the teacher. For example, the sherpa-student orchestration depicted in Figure 2 clearly has a social aspect: students will interact on the work shown by the sherpa student under the guidance of the teacher.

Things are actually more complex. For example, in the mirror configuration (Figure 4), a pair of students learns from observing another pair of students solving a problem, without the teacher's intervention, but within an orchestration that was designed by her. [START_REF] Trouche | Construction et conduite des instruments dans les apprentissages mathématiques : nécessité des orchestrations[END_REF] Overall, there clearly is a difference between Hoyles's approach, speaking of learners, interacting in the frame of communities of practice, and Trouche's approach, speaking of students, interacting in the frame of classroom didactical configurations designed by a teacher. conductor) wishes ''to hear'' in order to judge the students' performance, or the more personal and community-based norms tied to students' own developing conceptions and personal inclinations?

"Who orchestrates" is certainly an essential question. It seems to constitute a third terrain for confronting the two approaches.

The role of the teacher in orchestration

For the instrumental orchestration, the teacher has a central role, as "the orchestra conductor rather than a one-man's band" (Trouche, 2004, p. 299). The orchestra metaphor allows some variation, playing on the kind of orchestra -the jazz band offers room for student improvisation -, the choice of the score, the choice of the didactical configuration. But in each of these cases, the teacher is always central.

From the webbing perspective, the teacher can remain distant, and digital technology in itself seems to have the potential to orchestrate student activity, as phrased by (Hoyles et al., 2004, p. 319):

We simply wish to raise the profile of the potential role of the technological tools and the kinds of symbolic language and interactions that they might foster among learners. Consider, just as a simple example, a learning environment that typically develops where rows of computers are physically fixed one behind the other with little if any connectivity, and contrast this with one where students have wireless-connected laptops and can enjoy a hugely greater freedom to collaborate and share their ideas, both face-to-face and virtually. This process of breathing life into technology necessarily differs from one individual to another, if only because of differences between the kinds of things a student takes for granted, already knows, or is trying to understand. In so far as the artefact's properties can be thought of as ''orchestrating'' the actions and expressions of an individual or a group of learners, this orchestration is not invariant across different individuals.

The notions of webbing and orchestration aim to describe the way in which learners may develop a fluent and effective relationship with mathematics through technology, orchestration adding the role of teacher to support such a development.

A possible unified point of view

The two perspectives of webbing and orchestration seem to be engaged in a process of convergence, as Hoyles et al. (ibidem, p. 322) acknowledge:

Our two perspectives are united in recognising that if orchestration aims merely to bring about ''convergence'' of mathematical expression with official mathematical discourse, the potential of the technology will almost certainly be missed. Yet convergence is important, so two qualifications of the previous comment are in order. First, convergence for the students may take time -significant time over years rather than days or months. Second, the process of orchestration must take place at different levels, separated in time: the first level of orchestration being to foster the growth of situated abstractions (or, instrumented social and individual mathematical schemes) which establish a ''cognitive scaffolding'' for a second level of orchestration to bring about convergence or at least alignment through discussion of boundary objects. This second phase might be expected to take place over an extended period, and through a combination of collective activity in the classroom and individual work by students. In fact, both notions highlight a view on learning that considers mental constructions, i.e. schemes or structures, as crucial, and both see a potential for digital technology to support the construction process, by means of scaffolding and processes such as instrumentation and instrumentalization.

The CAME conference discussion took place within a "circle of experts", but had an impact on a larger community of research interested in digital technology in mathematics education [START_REF] Lagrange | Technology and Mathematics Education: a Multidimensional Study of the Evolution of Research and Innovation[END_REF]. This led, at an international level, to "rethinking the terrain".

Rethinking the terrain… and the concepts

The seventeenth ICMI Study entitled "Technology Revisited" had its study conference in Hanoï in 20064 . The title of its proceedings "Mathematics Education and Technology-Rethinking the Terrain" (Hoyles & Lagrange, 2010) reveals the deep evolution of this research domain from the first naive approach towards an acknowledgment of the complexity of integrating digital technology in regular mathematics classrooms, that also affects the notions of webbing and orchestration. This study opened new horizons related to the impact of Internet on learning and teaching: the opportunities for collaborative work between students, but also between teachers, thus evidencing the crucial role of connectivity. We will look at these evolutions through the window of the panel on connectivity and virtual networks held during this conference, which was chaired by Celia Hoyles [START_REF] Hoyles | Connectivity and Virtual Networks for Learning[END_REF]. This panel proposes five contributions, including one by Trouche and Hivon entitled "Connectivity: new challenges for the ideas of webbing and orchestrations".

Orchestrations as living entities

Trouche and Hivon's contribution describes the collaborative work of six teachers who carefully designed an orchestration of a mathematical activity in a calculator network environment. The organisation of tables and calculators (Figure 5) as well as a relevant choice of the various applications available are discussed. Orchestrations appear here as living entities in two respects:

-In the teachers' respect, orchestrations appear as the result of their collaborative work of together designing a priori orchestrations and of analysing the classroom implementations: "The cross-observations of teachers in their own classes helped them to create a distance from their own practice and to develop a reflexive attitude to the orchestration of students' activity" (Hoyles et al., 2010, p. 449); -In the students' respect, students no longer just play the music written by the conductor; rather they are composing part of the music themselves. The question, then, is how the teacher can create conditions to make the music not too different from his/her intentions, and to enrich the prepared partition with thesometimes unexpectedstudent improvisations.

As Dillenbourg and Jermann (2010, p. 527) claim, "The key difference between music orchestration and classroom orchestrations is that, when orchestrating a classroom, the score has often to be modified on the fly". As the initial notion of orchestration included didactical configurations and exploitations modes ( § 2.2), and as such did not focus on the dynamic adaptions made on the fly, Drijvers, Doorman and colleages (2010) introduced a third orchestration level of didactical configuration. If we see orchestrations as dynamic entities that emerge in cycles of preparation, adaptation on the fly and reflection, there is an interesting parallel between students engaging in instrumental genesis and teachers engaging in process of developing a repertoire of instrumental orchestration; a process of orchestrational genesis, so to say.

Orchestrating to foster situated abstractions and negotiate shared meanings

Comparing the sherpa configuration (Figure 2) and the radius configuration (Figure 5), the connectivity in the latter one clearly affords more flexible relationships between pupils. For Trouche and Hivon (Hoyles et al.,p. 448), through connectivity, "a new interactivity is fostered between the artefact and the student, and between students themselves: students convey their messages through the artefact, the artefact acts on the students enabling them to distance themselves from their productions thus freeing them to become more easily involved in peer exchanges. Thus the common space (Figure 6) becomes a space of debate and exchange that aims to elaborate a social 'mathematical truth'." . On the one hand, it is important to have in mind a necessary assistance (the notion of orchestration) of students' mathematical activity, and on the other, it is crucial to let the students free to think and establish connections (the idea of webbing)".

The ICMI Study panel suggests some converging points of view, both on the true nature of mathematical conceptualisation ( § 3.1) and on the power of interactions between learners ( § 3.2). The importance of the teacher ( § 3.3) is largely acknowledged by Hoyles (ibidem, p. 460): "[…] the teacher is crucial. But here we are delineating new, even more demanding roles for the teacher, to be aware -across not only her own classroom but those in remote locations -of the evolution of discussion, the mathematical substance of what is and what is not discussed, and the need all the while to find ways to keep students on task without removing the exploratory and fun elements of the work". These demanding roles for the teacher suggest an urgent research focus, in which teachers' development is considered: "Teachers are themselves involved in a process of instrumental genesis to develop artifacts into instruments for accomplishing their teaching tasks" (Drijvers, Kieran, & Mariotti, 2010, p. 112). The re-sourcing of teacher work is the topic of the next section.

RE-SOURCING TEACHER WORK

In the previous sections, we noticed that it is naïve to expect the process of webbing, which shares characteristics with the instrumental genesis central in the instrumental approach, to be autonomous and self-evident. Rather, it needs guidance by the teachers, and this is where the notion of instrumental orchestration fits in. To be able to provide this guidance, however, teachers' professional development is needed. The question, therefore, is how we can put into practice the notions of webbing and orchestration to study teacher behaviour and to inform teachers' professional development. This questionis addressed in the ZDM issue 45(7) entitled 'Re-sourcing teacher work and interaction: new perspectives on resource design, use and teacher collaboration', edited by Pepin, [START_REF] Gueudet | Collective work with resources: an essential dimension for teacher documentation[END_REF]. Three contributions to this benchmark issue will be discussed in below.

Towards a taxonomy of orchestrations?

The notion of instrumental orchestration can be used for different purposes. Whereas [START_REF] Trouche | Managing the Complexity of Human :Machine Interactions in Computerized Learning Environments: Guiding Students' Command process Through Instrumental Orchestrations[END_REF] initial paper on instrumental orchestration highlights the potential and the importance of the concept, Drijvers used instrumental orchestration primarily to observe teaching practices put into action by novice and expert teachers and to establish connections between these practices and the teachers' views on the role of digital tools in mathematics education [START_REF] Drijvers | The teacher and the tool: instrumental orchestrations in the technology-rich mathematics classroom[END_REF]. In a paper in the ZDM issue discussed here, this led to a tentative taxonomy of teaching practices, which is not claiming completeness; rather, a different teaching setting with other digital tools might lead to a different inventory [START_REF] Drijvers | Digital resources inviting changes in mid-adopting teachers' practices and orchestrations[END_REF]; see Figure 7). A small-scale follow-up study suggests that differences between expert and novice teachers (with respect to their experience of integrating of digital technology in teaching) seem to lie more in the quality and duration of the orchestrations than in the richness of the repertoire, even if novice teachers tend to be careful with using new, more 'adventurous' orchestrations in which they might feel less in control (Kaper, 2013, unpublished master thesis). For example, expert teachers were more efficient in dealing with technology-centred orchestrations, such as Technical-demo and Technical-support (see Figure 7). This highlights the importance of the quality of the orchestration, which so far remains largely unexplored.

Ruthven (2014) describes these different purposes, as he perceives them among the co-authors of the present paper, as follows:

This shift in the meaning and structure of "instrumental orchestration" between Trouche and Drijvers reflects their differing purposes: while Trouche is interested in examining potential strategies, Drijvers is seeking to describe observed patterns. [START_REF] Ruthven | Frameworks for analysing the expertise that underpins successful integration of digital technologies into everyday teaching practice[END_REF].

The Drijvers et al. paper not only shows a way of identifying teaching strategies with digital technology; it also shows how a tentative way of putting into practice a theoretical notion may impact on the concept itself. [START_REF] Drijvers | Digital resources inviting changes in mid-adopting teachers' practices and orchestrations[END_REF]

The Cornerstone Mathematics Project

In the same ZDM issue, Hoyles and colleagues report on the Cornerstone Mathematics Project, which addresses teachers' professional development through their participation in the project [START_REF] Hoyles | Cornerstone Mathematics: designing digital technology for teacher adaptation and scaling[END_REF]. In particular, teachers' adaptation of an existing technology-rich teaching sequence, their ownership and the impact of the collaboration with colleagues are investigated. It is interesting to consider this article's theoretical and methodological approach and its results, and to relate these to the notions of webbing and orchestration, and to other work presented in the same journal issue.

Concerning the theoretical orientation, it is remarkable that notion of webbing is absent in the paper, even if one of the foci is students' conceptual development, as a result of using digital technology. Interestingly, the authors do mention instrumental genesis and describe instruments as "systems with which the user gains fluency and expressive competence" (p. 1058). We wonder if the word 'system' in the previous quote could be related to the word 'structure' in description of webbing in the Noss and Hoyles 1996 book: "the structure that learners can draw upon and reconstruct for support"? In the 2013 paper we discuss here, the notions of orchestration and instrumentalisation are used, even if their meanings may in some cases be quite specific.

In addition to similarities in the theoretical framework, the Hoyles et al. 2013 study also makes methodological choices that are shared by others. For example, compared to the Drijvers et al. study reported in the same journal volume [START_REF] Drijvers | Digital resources inviting changes in mid-adopting teachers' practices and orchestrations[END_REF], the two studies share the use of an existing teaching sequence as the point of departure for a new sequence and a corresponding process of adaptation and professional development. Also, small-size communities of teachers are set up, and the communication within these communities is organized in a blended way through both face-to-face meetings and online facilities.

Finally, there is also some agreement on the findings reported in [START_REF] Hoyles | Cornerstone Mathematics: designing digital technology for teacher adaptation and scaling[END_REF] and in [START_REF] Drijvers | Digital resources inviting changes in mid-adopting teachers' practices and orchestrations[END_REF]. For example, it appeared difficult to make teachers engage in online communication, in addition to face-to-face meetings. Also, the importance of ownership that teachers should feel with respect to the teaching unit and its adaptation is a common conclusion. Adaptation does not necessarily imply adoption. Finally, the role of the community of colleagues is highlighted. This relates to the topic of teachers' documentational work and collaborative work, which will be addressed in the next section.

The documentational and collaborative work of teachers

A third contribution in the ZDM issue relates to teachers' collective work with resources [START_REF] Gueudet | Collective work with resources: an essential dimension for teacher documentation[END_REF]. The point of departure is that teachers nowadays have access to an immense and ever growing collection of teaching resources. Even if the internet is an important vehicle for dissemination, these resources are not necessarily technology related: interactive applets can be complemented by paper-on-screen documents such as book chapters or paper-and-pencil tasks. This myriad of resources now confronts the teacher with the challenge of finding, selecting, adapting and using the available teaching resources for the purpose of their own teaching. Is digital tools are provided to students, teaching resources are provided to teachers, and it is here that an analogy with instrumental genesis emerges: the process of teachers transforming resources into documents for their own teaching is called documentational genesis [START_REF] Gueudet | Towards new documentation systems for mathematics teachers[END_REF].

Figure 8. A representation of documentational genesis [START_REF] Gueudet | Towards new documentation systems for mathematics teachers[END_REF] This process, which teachers engage in, is depicted in Figure 8. [START_REF] Sabra | Collective design of an online math textbook: when individual and collective documentation works meet[END_REF] exemplified the kind of resource systems teachers can develop during their documentational genesis (Figure 9). Kieran and colleagues (2013) recently applied the notion of documentational genesis also to the work of the educational researcher.

Figure 9. A self representation of one teacher's system of resources [START_REF] Sabra | Collective design of an online math textbook: when individual and collective documentation works meet[END_REF] It should be noticed that, in case digital tools are involved, documentational genesis includes the teacher's personal instrumental genesis as well as her orchestrational genesis (see 4.1): a teachers' documentational activity includes a grounding instrumental genesis concerning the artifacts in use, and is followed by the design of instrumental orchestrations aiming at the integration of those artefacts in the teaching processes (grounding the orchestrational geneses). Finally, this process ends with the documentational geneses, fed by all the resources that the teacher encountered and gathered for her own needs. As is the case for instrumental genesis, these documentational geneses are complex and not easy to pursue in isolation. Therefore, it seems that collaboration among teachers, in which orchestrations are shared and co-designed, can be very fruitful. It is here that the notion of community of practice comes in. Even if it is not self-evident that groups of teachers working together form an efficient community of practice [START_REF] Drijvers | Digital resources inviting changes in mid-adopting teachers' practices and orchestrations[END_REF], the initiatives Hoyles and colleagues undertook to establish collaborative work by teacher through the NCETM and in the Cornerstone Mathematics project [START_REF] Hoyles | Cornerstone Mathematics: designing digital technology for teacher adaptation and scaling[END_REF] are promising.

As a conclusion of this section, the three papers mentioned here suggest some convergence, both from a theoretical and a methodological perspective, as well as in results. As an overall lesson, we learn that in-service teachers' professional development can be fostered by a joint work on technology-rich teaching sequences for which teachers feel ownership, and which is done in small-scale communities through blended means of communication.

FUTURE DIRECTIONS TOWARDS EXPLORING TERRA INCOGNITA

How do the above reflections on the notions of webbing and orchestration guide future research agendas?

Teachers' collaborative work seems to constitute a true terra incognita to be explored: "The way digital technologies can support and foster today collaborative work, at a distance or not, between students or between teachers, and also between teachers and researchers, and the consequences that this can have on students' learning processes, on the evolution of teachers' practices is certainly one essential evolution that educational research has to explore in the future. As mentioned above, most of this space is still for us nearly terra incognita" (Artigue, in Hoyles & Lagrange, 2010, p. 473).

Collective work with resources appears to be "an essential dimension for teacher documentation" [START_REF] Gueudet | Collective work with resources: an essential dimension for teacher documentation[END_REF], and for this reason an essential field for future research. The emergence of online teacher associations, such as Sésamath in France [START_REF] Sabra | Collective design of an online math textbook: when individual and collective documentation works meet[END_REF] provides interesting opportunities to analyse and better understand the interaction between individual and collective documentational geneses.

New contexts for learning are offered by MOOCs (Massive Open Online Courses), which confront teams of teachers to, in many cases, several thousands of students. These new formats allow students to learn through different types of complex social interactions on the web, and, as such, challenge the usual repertoire of orchestrations. This development forms a new opportunity to rethink the relationships between orchestrations and webbing.

For investigating these new fields, new methodologies are needed, as well as new theories: "…teachers's actions in supporting new communities of practice are recognised as crucial, and new roles for the teacher noted, although it is acknowledged that these roles have as yet been undertheorised" (Hoyles & Lagrange, 2010, p. 423). It is this fascinating field of technological, social and educational developments that we explore, gratefully capitalizing on the work done by Celia Hoyles and her colleagues over the last decades.

Figure 1 .

 1 Figure 1. A trace of the scheme Isolate-Substitute-Solve on a TI-89 calculator.

Figure 2 .

 2 Figure2. The sherpa-student configuration(Trouche, 2004, p. 298)

Figure 3 .

 3 Figure 3. A musical notation for integrated scripts[START_REF] Dillenbourg | Technology for classroom orchestration[END_REF]

Figure 4 .

 4 Figure 4. The mirror configuration[START_REF] Trouche | Construction et conduite des instruments dans les apprentissages mathématiques : nécessité des orchestrations[END_REF]

Figure 5 .

 5 Figure 5. From the intended configuration by the manufacturer to the radius configuration chosen by the teachers

Figure 6 .

 6 Figure 6. The classroom screen displaying the different student calculator screens becoming a common work spaceSuch a connected configuration invites a flexible view on mathematics learning, in which shared meanings (in this case on the notion of function) emerge. Finally,Trouche and Hivon (ibidem, p. 451) stress "the need to rethink the notion of orchestration and the notion of webbing[…]. On the one hand, it is important to have in mind a necessary assistance (the notion of orchestration) of students' mathematical activity, and on the other, it is crucial to let the students free to think and establish connections (the idea of webbing)".

Figure 7 .

 7 Figure 7. Overview of observed orchestrations[START_REF] Drijvers | Digital resources inviting changes in mid-adopting teachers' practices and orchestrations[END_REF]

Binôme observé Binôme observant

  Hoyles et al. (ibidem, p. 316) outline this as follows.

	Calculatrice
	Rapports de
	recherche
	Tablette de
	rétroprojection
	Feuilles
	d'observation
	Orchestration/instrumentation is a felicitous metaphorical pairing, which captures something of
	the relationships involved. One striking issue about the metaphor (although bearing in mind that

a metaphor should not be interpreted too literally) is this: what is the analogue of music in the orchestration of mathematical instruments? Presumably the answer is mathematics, but what kind of mathematics? The production of ''official'' mathematics which the teacher (i.e.,

The Third CAME (Computer Algebra in Mathematics Education) symposium was held in Reims (France) in

2003,focusing on "Learning in a CAS Environment: Mind-Machine Interaction, Curriculum & Assessment". 2 Contributions are available on the conference website (http://www.lkl.ac.uk/research/came/events/reims/). The papers by[START_REF] Hoyles | On the integration of digital technologies into mathematics classrooms[END_REF] and[START_REF] Trouche | Managing the Complexity of Human :Machine Interactions in Computerized Learning Environments: Guiding Students' Command process Through Instrumental Orchestrations[END_REF] emerged from these contributions.3 Using the same metaphor, Dehaene (2010, p. 221) identifies the internal orchestration of distributed neuronal networks as a central question for the neurosciences.

Its Discussion Document « Technology revisited » is available at http://www.mathunion.org/fileadmin/ICMI/files/Digital_Library/DiscussionDocs/DD_icmiStudy17_02.pdf.