19–21 nov. 2025
IHES
Fuseau horaire Europe/Paris

Phase Transitions and Mittag-Leffler Functions for Critical Schemes Under the Gibbs Model

21 nov. 2025, 10:00
50m
Centre de conférences Marilyn et James Simons (IHES)

Centre de conférences Marilyn et James Simons

IHES

Le Bois-Marie 35, route de Chartres 91440 Bures-sur-Yvette

Orateur

Cyril Banderier (LIPN)

Description

Composition schemes are ubiquitous in combinatorics, number theory, statistical mechanics and probability theory.
We give a unifying explanation to various phenomena observed in the combinatorial and statistical physics literature in the context of $q$-enumeration (models where objects with a parameter of value $k$ have a Gibbs measure/Boltzmann weight $q^k$).
For structures enumerated by a composition scheme, we prove a phase transition for any parameter having such a Gibbs measure: for a critical value $q=q_c$, the limit law of the parameter is a two-parameter Mittag-Leffler distribution, while it is Gaussian in the supercritical regime ($q>q_c$), and it is a Boltzmann distribution in the subcritical regime ($0 We also explain previously observed limit laws for pattern-restricted permutations, and a phenomenon uncovered by Krattenthaler for the wall contacts in watermelons.
(Based on the article https://arxiv.org/abs/2311.17226 by Cyril Banderier, Markus Kuba, Stephan Wagner, Michael Wallner).

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