LFCS Seminar: 9 October 2018 - Matthew Jenssen

Title: Algorithms for #BIS-hard problems on Expander Graphs

Abstract:

We give an FPTAS and an efficient sampling algorithm for the high-fugacity hard-core model on bounded-degree bipartite expander graphs and the low-temperature ferromagnetic Potts model on bounded-degree expander graphs.  The results apply, for example, to random (bipartite) $\Delta$-regular graphs, for which no efficient algorithms were known for these problems (with the exception of the Ising model) in the non-uniqueness regime  of the infinite $\Delta$-regular tree. Joint work with Peter Keevash and Will Perkins.