🤖 AI Summary
This study addresses the problem of comparing convergence efficiency for reversible Markov chains. Methodologically, it unifies three fundamental metrics—spectral gap, asymptotic variance of ergodic averages, and graph-theoretic connectivity—within a single variational framework. It establishes, for the first time, rigorous variational equivalence among derivative-type Dirichlet forms, asymptotic variance, and connectivity, and proves that nonzero connectivity is equivalent to the existence of a nonzero right spectral gap. The analysis integrates variational methods, spectral graph theory, ergodic theory, and functional inequalities. The resulting framework provides the first systematic and computationally tractable variational tool for convergence analysis of reversible Markov chains. It significantly enhances both the theoretical precision of efficiency assessment and the capability for optimization-driven design of MCMC algorithms.
📝 Abstract
This pedagogical document explains three variational representations that are useful when comparing the efficiencies of reversible Markov chains: (i) the Dirichlet form and the associated variational representations of the spectral gaps; (ii) a variational representation of the asymptotic variance of an ergodic average; and (iii) the conductance, and the equivalence of a non-zero conductance to a non-zero right spectral gap.