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Sage Days 73 in Oaxaca, Mexico May 0407 2016
Sage is an open source software for mathematics. This is the webpage for the Sage workshop prior to the conference Flat Surfaces and Dynamics of Moduli Space to be held in Oaxaca May 0813. The aim is to:
 introduce Sage to people from Oaxaca or assisting to the conference
 have program and code presentations about geometry and dynamics of surfaces
 help people to implement their own projects
The workshop will start wednesday 04 morning and ends saturday 07 after lunch. It will take place at Punto Mexico Conectado @ Oaxaca in calzada Madero numero 101.
Previsional schedule

Wednesday 4 May 
Thursday 5 May 
Friday 6 May 
Saturday 7 May 
09:00  10:00 
registro y instalación 
coding sprint 
? 
? 
10:00  11:00 
presentación de Sage 
coding sprint 
? 
? 
11:00  11:30 
té y café 
coffe break 
coffe break 
coffe break 
11:30  13:00 
actividades practicas 
coding sprint 
? 
? 
13:00  14:30 
lunch break 
lunch break 
lunch break 
lunch break 
14:30  15:30 
presentation / discussion 
coding sprint 
? 
FREE 
15:30  17:00 
tutorial: symbolic vs numeric 
coding sprint 
? 
FREE 
17:00  17:30 
coffe break 
coffe break 
coffe break 
FREE 
17:30  18:00 
Pat Hooper's demo 
Vincent's demo 
Vincent's demo 
FREE 
18:00  19:00 
coding spring 
status report 
? 
FREE 
Talks
Presentación de Sage, (jupyter notebook Sage presentation.ipynb)
symbolic vs numerics in Sage (tutorial, wednesday 15:30  17:00, Vincent Delecroix)
There are many ways to deal with numbers within Sage (algebraic numbers, floating points, intervals, ...). We will present and illustrate pros and cons of all of them on some concrete problems: root finding, integration, solving ordinary differential equations. symbolic_vs_numeric.rst
Flatsurf (demo, ¿when?, Pat Hooper)
the flatsurf package (demo, ¿when?, Vincent Delecroix)
computing Lyapunov exponents of the Teichmueller flow (demo, ¿when?, Charles Fougeron)
developing tools (tutorial, ¿when?, ¿who?)
git, the Sage trac server, mailing lists (sagedevel, sagesupport, pariusers, etc) and forums (ask sagemath).
 ? class howto ?
 ? (tutorial) SL2Z and triangle group code in Sage
? (tutorial) graphs and digraphs in Sage (Sage graph stuff and possibly bliss software, nauty and Traces, igraph, ...)
Projects
Teichmûller polynomials
people: Ferrán
 need traintracks automata with decorations. Then compute effectively dilatations in a given fibered face, Thurston norm, etc
Explore Thierry's Coulbois traintrack code
flatsurf Package(s)
 More for infinite translation surfaces (Pat)
 (easy) add ThurstonVeech construction into the flatsurf package
merge the two flatsurf projects https://github.com/videlec/sageflatsurf and http://www.labri.fr/perso/vdelecro/flatsurf.html (Pat, Vincent)
visualize Teichmueller spaces
people: Maxime, Kasra
 geodesics, balls, triangles, ... Needs computing Teichmueller maps, i.e. solving PDE
 nice 3d plots to make animations of geodesic in Teichmueller space
visualize the translation structure induced by a not so nice differential
people: Anja
other projects
 Compute properties of Coxeter or Artin groups (normal forms, ...)
 Incidence relations for vector space over Z/2Z (done!)
 Subgroups of SL(2,R) given from generators. Design an algorithm that given a finite set of matrices in SL(2,R) answers whether the group generated by these is
 not discrete
 has finite covolume
 has infinite covolume
 Generating saddle connections in a given surface and study their statistics *efficiently* (Grace)
 add Lyapunov exponents computation in the flatsurf package (Charles, Vincent)
 Affine interval exchange transformations: rotation number for affine circle homeos, generalized Rauzy induction, hyperbolicity, periodic points, ... (Charles)
 Teichmueller flow for genus 1 quadratic differentials with Riemann theta functions (Charles)
... add your own project ...
Existing programs about translation surfaces
 Alex Eskin code (saddle connection exploration + decomposition in cylinders)
various programs by Ronen Mukamel (Delaunay triangulations, Teichmueller curves especially in genus 2)
Vincent Delecroix flatsurf package (mostly interval exchanges and square tiled surfaces, but a bit of topology)
Vincent Delecroix and Pat Hooper drawing program
Charles Fougeron code for Lyapunov exponents of strata coverings (see trac ticket #16102)
Chris Swierczewski Riemann surfaces package
Organizers
Preliminary list of participants (to be confirmed)
Thierry Monteil (might attend remotely)
Chris Swierczewski (might attend remotely)
Support
This workshop is supported by the ERC H2020 project OpenDreamKit and Punto Mexico Conectado @ Oaxaca.