Seminars - GALaC LRI Paris-Sud

GALaC team seminar

The GALaC team seminar is organized on a regular basis on Friday at 14:00 in the PCRI building (650) at LISN. Recent and up-coming seminars

Plateau Saclay Combinatorics Seminar

The Plateau Saclay Combinatorics Seminar is held on several Mondays at 11am in room Philippe Flajolet (top floor on the left) at LIX. It is co-organized by the Combi team of LIX and the GALaC team. The mailing list for this seminar is combi_lix_lri@services.cnrs.fr. Subscribe to this ...

Plateau Saclay Algorithms Seminar

The Plateau Saclay Algorithms Seminar is held every other Friday afternoon in LIX. This working group is partially supported by Labex DigiCosme (Digital worlds: distributed data, programs and architectures). If you do wish (or not) to receive any emails from this seminar, you can subscribe or unsubscribe from the mailing ...

Lattice structures of Gog and Magog triangles

jeu. 27 mars 2025 -- Ludovic Schwob (LIGM, Combi)

summary: Gog and Magog triangles are simple combinatorial objects which are equienumerated. Howewer, the problem of finding an explicit bijection between these has been an open problem since the 80’s. These are related to other interesting objects such as alternating sign matrices, plane partitions or aztec diamond tillings.
All ...

Une nouvelle description des treillis m-cambriens

jeu. 13 mars 2025 -- Clément Chenevière (LISN, GALaC)

summary:

Les treillis cambriens, introduits par N. Reading en 2006, sont une généralisation du treillis de Tamari, à tout choix d'élément de Coxeter, dans tout groupe de Coxeter fini. Le treillis de Tamari correspond au "type A linéaire". Ces ordres partiels admettent plusieurs descriptions, non trivialement équivalentes. Celles-ci donnent ...

Proper conflict-free colourings of graphs

ven. 21 février 2025 -- Quentin Chuet (LISN, GALaC)

summary: Given a graph \(G\) of maximum degree \(\Delta\), the proper colouring problem asks for the minimum number of colours that can be assigned to the vertices of \(G\) such that no pair of adjacent vertices are given the same colour; it is easy to show that at most \(\Delta ...

Alternating and nondeterministic plane-walking automata

ven. 14 février 2025 -- Pacôme Perrotin (LISN, Galac)

summary: Plane-walking automata were introduced by Salo & Törma to recognise languages of two-dimensional infinite words (subshifts), the counterpart of 4-way finite automata for two-dimensional finite words. We extend the model to allow for nondeterminism and alternation of quantifiers. We prove that the recognised subshifts form a strict subclass of sofic ...