The Parisi ultrametricity conjecture

Abstract

In this paper we prove that the support of a random measure on the unit ball of a separable Hilbert space that satises the Ghirlanda-Guerra identities must be ultrametric with probability one. This implies the Parisi ultrametricity conjecture in mean-eld spin glass models, such as the Sherrington-Kirkpatrick and mixed p-spin models, for which Gibbs measures are known to satisfy the Ghirlanda-Guerra identities in the thermodynamic limit.