Session 27. Probabilistic and Extremal Combinatorics

The condensation phase transition in random graph coloring

Amin Coja-Oghlan, Goethe University Frankfurt, Germany
The talk is based on the joint work with Victor Bapst, Samuel Hetterich, Felicia Rassmann, Dan Vilenchik
Based on a non-rigorous formalism called the ``cavity method'', physicists have put forward intriguing predictions on phase transitions in discrete structures. One of the most remarkable ones is that in problems such as random \(k\)-SAT or random graph \(k\)-coloring, very shortly before the threshold for the existence of solutions there occurs another phase transition called {\em condensation} [Krzakala et al., PNAS 2007]. The existence of this phase transition appears to be intimately related to the difficulty of proving precise results on, e.g., the \(k\)-colorability threshold as well as to the performance of message passing algorithms. In random graph \(k\)-coloring, there is a precise conjecture as to the location of the condensation phase transition in terms of a distributional fixed point problem. Here we prove this conjecture for \(k\) exceeding a certain constant \(k_0\).
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