MOWGLI - A New Approach for the Content Description in Digital + Documents

The acronym MOWGLI stands for "Mathematics On the Web: Get it by Logic and +Interfaces". MOWGLI is an European Project founded by the European Community +in the ``Information Society Technologies'' (IST) Programme. The partners are +the University of Bologna, INRIA (Rocquencourt), the German Research Centre +for Artificial Intelligence (DFKI, Saarbruecken), the Katholieke Universiteit +Nijmegen, the Max Planck Institute for Gravitational Physics (Albert Einstein +Institute, Golm), Trusted Logic (Paris) and TU Berlin.

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The aim of the project is the study and the development of a technological +infrastructure for the creation and maintenance of a virtual, distributed, +hypertextual library of mathematical knowledge based on a content description +of the information. Currently, almost all mathematical documents available on +the Web are marked up only for presentation, severely crippling the +potentialities for automation, interoperability, sophisticated searching +mechanisms, intelligent applications, transformation and processing. The goal +of MOWGLI is to overcome these limitations, passing from a machine-readable to +a machine-understandable representation of the information, and developing the +technological infrastructure for its exploitation.

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The project deals with problems traditionally belonging to different +scientific communities: digital libraries, Web publishing, automation of +mathematics and computer aided reasoning. Any serious solution to the complex +problem of mathematical knowledge management needs a co-ordinated effort of +all these groups and a synergy of their different expertise. MOWGLI attempts +to build a solid co-operation environment between these communities. The +current paper will concentrate on the aspects related to digital libraries.

1. Aims and mission of MOWGLI

After a ten years period of electronic publishing in mathematics we are still +confronted with slightly enhanced electronic versions of printed publications. +Almost all mathematical documents available on the Web are marked up only for +presentation, if such an enhancement is available at all. Only a minority of +documents try to care about some of the potentialities for automation, +interoperability, sophisticated searching mechanisms, intelligent +applications, transformation and processing. But these approaches could be +considered as first preliminary steps towards an electronic document providing +all these facilities. Hence, the goal of MOWGLI is to overcome these +limitations, passing form a machine-readable to a machine-understandable +representation of the information, and developing the technological +infrastructure for its exploitation.

In order to reach this goal MOWGLI has to deal with problems traditionally +belonging to different scientific communities: digital libraries, Web +publishing, automation of mathematics and computer aided reasoning. To our +knowledge, MOWGLI is the first attempt to build a solid co-operation +environment between these communities. In principle, any serious approach for +providing good tools for mathematical knowledge management needs a +co-ordinated effort of several partners from the above mentioned communities +and a synergy of +their different expertise. The choice of partners for the took this condition +into account, as can be seen below.

The goals of MOWGLI largely overlap with the aims of the so called "Semantic +Web" [14]. +Associating meaning with content or establishing a layer of machine +understandable data will allow automated agents, sophisticated search engines +and interoperable services and will enable higher degree of automation and +more intelligent applications. The ultimate goal of the Semantic Web is to +allow machines to share and exploit knowledge in the Web way, i.e. without +central authority, with few basic rules, in a scalable, adaptable, extensible +manner. However, the actual development of the Semantic Web and its +technologies has been hindered so far by the lack of large scale, distributed +repositories of structured, content oriented information. The case of +mathematical knowledge, the most rigorous and condensed form of knowledge, is +paradigmatic. The World Wide Web is already now the largest single resource of +mathematical knowledge, and its importance hopefully be increased by the +emerging display technologies like MathML.

Machine understandable information will make possible to offer added-value +services like: +

Due to its rich notational, logical and semantic structure, mathematical +knowledge is a main case study for the development of the new generation of +semantic Web systems. The aim of the MOWGLI project is both to help in this +process, as well as pave the way towards a really useful virtual, distributed, +hyper-textual resource for the working mathematician, scientist or engineer.

2. Standards and Tools

Current standards for electronic publishing in mathematics are mainly +presentation oriented. New tools for the management and publishing of +mathematical documents are in development like MathML +[3], OpenMath, OMDoc +([17],[18]) and integrated with different +XML technology [7] (XSLT [8], RDF +[4], [5], SOAP [6], ...). +All these languages cover different and orthogonal +aspects of the information and its management; our aim is not to propose a new +standard, but to study and to develop the technological infrastructure +required for taking advantage of the potentialities of all of current +standards and those which are likely to be established in the near future.

MOWGLI makes an essential use of standard XML technology and aspires to +become an example of ``best practice'' in its use, and a pioneering leading +project in the new area of the Semantic Web [12]. +In particular, the potentialities of +XML will be deeply explored in the following directions: +

MathML [3], introducing for the first time a content markup +layer in parallel +with a presentational one, has indubitably been a pioneering project towards +the mining of the mathematical treasure available on the web. Still, its +limitations are evident as well: +

Similarly, the creation and maintenance of the library as a distributed +repository, and the crucial aspect of managing the information in the ``web +way'' requires a light but powerful communication protocol, overcoming some of +the limitations of HTTP (SOAP [6] looks as a promising +solution).

Metadata will eventually require a fairly sophisticated model, much beyond +what is currently offered by typical metadata models as the Dublin-Core system +[1]. Here, RDF (Resource Description Framework) +([4], [5]) looks as the right +framework for developing the model, providing a general architectural model +for expressing metadata and a precise syntax for the encoding and interchange +of these metadata over the Web.

The fact of encoding also the microscopic, logical level of mathematics opens +the possibility to have completely formalised subsystems of the library +([9],[10]), which could be checked +automatically by standard tools for the +automation of formal reasoning and the mechanisation of mathematics (proof +assistants and logical frameworks +([15],[16]). At the same time, any of these +tools could be used as an authoring system for documents of the library, by +simply exporting their internal libraries into XML, and using stylesheets to +transform the output into a standard, machine-understandable representation, +such as MathML content markup or OpenMath. In MOWGLI we shall use the COQ +Proof Assistant of INRIA [13] as a paradigmatic example of +these applications.

An alternative route for the creation of content-based mathematical +information from standard digital repositories by means of a suitable +LaTeX-based authoring system will be explored by the Albert Einstein +Institute. They publish the "Living Reviews in Relativity" +[2], a solely +electronic journal on the Web, which provides refereed, regularly updated +review articles on all areas of gravitational physics. AEI will develop a +LaTeX-based authoring tool interfacing with MOWGLI, and serve as a showcase to +demonstrate how content-mark-up in mathematics improves the usability and +information depth of electronic science journals.

3. A minimal technological infrastructure

It is clear that the creation and maintenance of large repositories of +content-based mathematical knowledge can only be conceived as a cooperative +and distributed process, comprising not only the creation of documents, but +also libraries of notational rules, metadata and management tools. The crucial +point is to build a minimal infrastructure to start up this process, so that +more and more tools can be added by interested parties. All these +considerations lead to two requirements for the developments in MOWGLI: +

In this way, we put no barrier to third party development and, every time a +standard technology or tool is improved, we can simply benefit of the new +implementation with minimal effort.

The MOWGLI architecture is essentially based on three components, which are +distribution sites, standard browsers and plug-outs, and active components, +such as XSLT processors, to elaborate the information. Distribution sites are +simply HTTP and FTP servers, widespread throughout the world; user browsers +are HTTP clients and run on the user host. We do not require any other +components to run on a specific host. Active components must provide answers +to browsers, requiring an HTTP server interface; they must also ask data to +distribution sites, acting as HTTP clients. Hence, MOWGLI is essentially +conceived as an HTTP pipeline.

The module client of the distribution sites is the "getter", which maps URIs +to URLs and hence documents, offering functionalities similar to the APT +packet management system +(http://www.debian.org).

The main active component is the XSLT stylesheet manager, whose typical +functionality is the application of a list of stylesheets (each one with the +respective list of parameters) to a document. However, other components may be +added in a completely modular way. This is exactly the content-based +architectural design of future web system enabled by XML technology.

4. The contributions from the participants

The concrete background for the work in MOWGLI is represented by the +activities at the participating institutions. Though details could easily be +obtained from the MOWGLI web-page +(http://mowgli.cs.unibo.it) some short +remarks on this background should be made here.

The Department of Computer Science at the University of Bologna is the only +educational institution in Italy to be affiliated to W3C. They care about the +coordination of the project. The HELM project (Hypertextual Electronic Library +of Mathematics, +http://www.cs.unibo.it/helm, see also +[12]) is active in +Bologna since 1999. It is one of the systems of reference mentioned in the +previous section.

INRIA (Institut National de Recherche en Informatique et Automatique) is a +French institution located in Rocquencourt. They pursue two projects of +importance for MOWGLI: the Lemme project, introducing and developing formal +methods for use in writing scientific computing software, and the LogiCal +project, which developed the Coq proof assistant (see +[13]).

The German Research Center for Artificial Intelligence (DFKI) is based in +Kaiserslautern and Saarbruecken. Its main mission is technology transfer, i.e. +to move innovations in Artificial Intelligence from the lab to the market +place. Its main MOWGLI-related prototypical product so far has been the +Web-based learning environment ActiveMath that integrates several external services.

The Subfaculteit Informatica of Katholieke Universiteit Nijmegen hosts a +broad experience in logic, formal methods and theorem proving. They are +involved in several research activities in this domain as the EC sponsored +Network "TYPES", the FTA project (Fundamental Theorem of Algebra), the EC +Working group Calculemus which also deals with OpenMath et al.

The role of the Albert Einstein Institute (MPG, Golm) near Potsdam has been +described above already. They provide a test bed with the Living Reviews which +will represent the important link to the domain of mathematical publishing. +This also is the main concern of the partner TU Berlin which is formally +associated to AEI caring about the exploitation and information dissemination +for MOWGLI.

Trusted Logic makes the group complete. This is a French start-up company, +which offers a wide range of efficient and secure solutions of smart cards and +terminals in a wide range of areas. Their development methodology includes a +permanent concern of quality and security aspects.

As it is common for projects like MOWGLI the cooperation between the partners +is regulated by workpackages and a time schedule for the deliveries. But the +project started formally in March 2002. Hence these things are still theory, +and it will be subject of the next report on MOWGLI to describe, how theory +came into practise.

BIBLIOGRAPHY

+Prof. Dr. Andrea Asperti
+Dipartimento di Scienze dell Informazione
+Universita degli Studii di Bologna
+Via di mura Anteo Zamboni VII
+I - 40127 Bologna
+Italy +

+Prof. Dr. Bernd Wegner
+Fakultaet II, Institut fuer Mathematik
+TU Berlin, Sekr. MA 8-1
+Strasse des 17. Juni 135
+D - 10623 Berlin
+Germany +

MOWGLI - A New Approach for the Content Description in Digital Documents

Andrea Asperti, University of Bologna, and Bernd Wegner, TU Berlin

Abstract:

1. Aims and mission of MOWGLI

2. Standards and Tools

3. A minimal technological infrastructure

4. The contributions from the participants

BIBLIOGRAPHY