next up previous
Next: Central Limit Theorem Up: Markov Chain Convergence Previous: Harris Recurrence

Geometric Ergodicity

A stronger property is geometric ergodicity. For any signed measure tex2html_wrap_inline2459 on tex2html_wrap_inline2343 , let tex2html_wrap_inline3665 denote the total variation of tex2html_wrap_inline2459 . A Markov chain is geometrically ergodic if there exists a constant r ;SPMgt; 1 such that

displaymath3671

This is implied (Meyn and Tweedie, 1993, Theorem 15.0.1) by the geometric drift condition: there exists a function tex2html_wrap_inline3673 , constants tex2html_wrap_inline3675 and tex2html_wrap_inline3677 , and a small set tex2html_wrap_inline3657 such that

  equation557

Any V that satisfies the geometric drift condition is unbounded off small sets (when the chain is aperiodic). Hence the geometric drift condition implies the drift condition for recurrence.

proposition560

proof563

It should be noted that neither of these proofs has any novelty. They follow exactly the logic of the proofs for the Strauss process sampler given in Geyer and Møller (1994). The only point of repeating them here is to show that the same argument works for any point process with unnormalized density having bounded conditional intensity.



Charles Geyer
Fri Jul 5 15:26:21 CDT 1996