Strong Spatial Mixing for Colorings on Trees and its Algorithmic Applications (Zongchen Chen)

Abstract

Strong spatial mixing (SSM) is an important quantitative notion of correlation decay for Gibbs distributions arising in statistical physics, probability theory, and theoretical computer science. A longstanding conjecture is that the uniform distribution on proper q-colorings on a D-regular tree exhibits SSM whenever q >= D+1. Moreover, it is widely believed that as long as SSM holds on bounded-degree trees with q colors, one would obtain an efficient sampler for q-colorings on all bounded-degree graphs via simple Markov chain algorithms. We show SSM for q-colorings on all trees of maximum degree D whenever q >= D+3, almost fully resolving the first conjecture. Towards sampling, we establish optimal mixing of the Glauber dynamics for q-colorings on all graphs of maximum degree D and sufficiently large girth whenever q >= D+3. Joint work with Kuikui Liu, Nitya Mani, and Ankur Moitra.

Time

2023-11-30  10:00 - 11:00   

Speaker

Zongchen Chen, University at Buffalo

Room

Room 308