2022/09/01 by Wolfer, Geoffrey, Kontorovich, Aryeh · 1 citation
#FOS: Mathematics #Probability (math.PR) #Statistics Theory (math.ST)
paper · doi:10.48550/arxiv.2209.00175
We show that the minimax sample complexity for estimating the pseudo-spectral gap γps of an ergodic Markov chain in constant multiplicative error is of the order of Θ( \frac1γps π⋆ ), where π_⋆ is the minimum stationary probability, recovering the known bound in the reversible setting for estimating the absolute spectral gap [Hsu et al., 2019], and resolving an open problem of Wolfer and Kontorovich [2019]. Furthermore, we strengthen the known empirical procedure by making it fully-adaptive to the data, thinning the confidence intervals and reducing the computational complexity. Along the way, we derive new properties of the pseudo-spectral gap and introduce the notion of a reversible dilation of a stochastic matrix.