Workshop LISA

FRUMAM, Marseille, June 3 - 6, 2019

This is the second annual meeting of the ANR group Lipschitz Geometry of Singularities (LISA). There will be several talks discussing open problems, questions, and techniques broadly related to the Lipschitz geometry of real and complex singular spaces.
The workshop will take place at the FRUMAM, in the Campus Saint-Charles of the Aix-Marseille University, from Monday, June 3rd to Thursday, June 6th, 2019.

Organizing committee: Lorenzo Fantini, Anne Pichon.


There will be a minicourse on Moderately Discontinuous Homology, jointly given by and regular talks by


  Monday Tuesday Wednesday Thursday
10:30-11:00   Coffee Coffee Coffee
12:00-14:30 Lunch Lunch Social Lunch Lunch
15:30-16:00 Coffee Coffee Coffee  
17:00-18:00     Meeting of the
ANR members


Minicourse: "Moderately Discontinuous Homology"

Joint work by: J. Fernandez de Bobadilla, S. Heinze, M. Pe Pereira, E. Sampaio.
Moderately Discontinuous Homology is a new algebraic topology invariant specially suited to study the Lipschitz Geometry of subanalytic sets. It is a Homology Theory having values in diagrams of groups, each of them called the MD Homology group associated with a given "discontinuity parameter". It satisfyies adequate forms of all axioms and computational tools of an ordinary homology theory: relative homology sequence, the value at a "point", Lipschitz homotopy invariance, Mayer-Vietoris, excision and the spectral sequences associated with filtrations and Cech coverings. A distinguishing feature of the theory is the functoriality for maps allowing a controlled type of discontinuities in the Lipschitz sense.
Besides being quite computable, it is able to capture the outer metric Lipschitz phenomena, and can be used as an invariant obstructing Lipschitz normally embedded in certain cases. As an example we will fully compute the invariant for complex plane curve germs for the outer metric, and show, in the irreducible case that it recovers all Puiseux pairs (we also compute the the non irreducible case in terms of the Eggers tree).
In the case of arbitrary dimension germs with the outer metric it recovers the number of irreducible components of the tangent cone, the relative multiplicities, and that it is powerful enough to characterize the smooth germ.


Practical informations

If you are interested in attending the workshop you can get in touch with Lorenzo Fantini and/or Anne Pichon.

The talks will take place on the Conference Room at the second floor of the FRUMAM, in the St. Charles campus, just north of the main station. Here's a maps of the campus. The entrance of the campus is in Place Victor Hugo, in front of the station's north exit (on the right if you are coming from the platforms), at GPS coordinates 43°18'16.7"N,5°22'42.6"E (the link will take you to Google maps); to enter tell the security guards there that you are coming for the LISA Workshop, they should have a list of all the participants. The entrance of the FRUMAM is on the map linked above, but it can be a bit hard to find, its coordinates are 43°18'21.1"N,5°22'48.2"E. Go up to the second floor and walk through the door on the right, the Conference Room is at the end of the corridor.

For your accommodation, here are a couple of nice and reasonably priced hotels close to the Vieux Port, about 10/15 minutes walking from the FRUMAM:

The participants are free to explore the city during the lunch breaks. Here are a couple of simple places within reasonable walking distance from the FRUMAM that we recommend:

There will be a social lunch on Wednesday, at the Café l'Écomotive.

This workshop is founded by the following institutions: ANR LISA, FRUMAM, GDR Singularités et Applications, Institut de Mathématiques de Marseille, Labex Archimède.