## Collective residencies / Olot

### MATHEMATICS

From Monday, 27 February 2017 to Friday, 10 March 2017

### Community of practice

**Mathematical Open Source Softwares at FABER**

Many mathematical softwares and more generally scientiﬁc softwares are hold by companies (e.g. Maple, Matlab, Mathematica, Magma). Because of the low demand and high need of these softwares a license is likely to cost around 50 000 Euros a year to a university.

This way of making software is not viable for several reasons:

1. They are not accessible to the general public despite the fact that most of them are being the work of people working in public institutions.

2. The license restriction is sometimes the cause of catastrophic disparition of softwares (e.g. MuPAD)

3. It is not possible to see how softwares are made but this is crucial in science: a bug can lead to dramatic errors in scientiﬁc investigation.

In the mid-eighties, some people realized that in order to have a sane environment for softwares (not necessarily scientiﬁc), one needs license that forces the programmers to make the software free with the source code accessible. This is the beginning of the GNU project leaded by Richard Stallman.

There are many open source projects dealing with mathematics: ﬂint http://flintlib.org/, polymake https://forum.polymake.org/, GAP http://www.gap-system.org/, and many more. Most of them are highly specialized and reﬂect the interest of a restricted community. The aim of the software SageMath http://sagemath.org started in 2005 by William Stein is to bring a common interface to all these softwares. Since the very ﬁrst day SageMath has been released as a GPL program which means that it is free and with its source code available.

Our aim during this stay at FABER is to bring experts in some of the components of SageMath in order to work on what are called polytopes. This has a lot of interesting applications outside of the research area of the participants.

### Residents

#### SIMON KING

Mathematician#### VINCENT KLEIN

Computer scientist#### THIERRY MONTEIL

Researcher#### ANDREAS PAFFENHOLZ

Mathematician#### MARCELO FORETS

Mathematician#### JULIAN PFEIFLE

Mathematician#### VINCENT DELECROIX

Mathematician and computer scientist#### JEAN-PHILIPPE LABBÉ

Mathematician#### MATTHIAS KÖPPE

Mathematician#### MORITZ FIRSCHING

Mathematician#### AUREL PAGE

Mathematician#### MARC MASDEU

Mathematician### Opinions

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