Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2023/iii/paper-216/2/c/solution

Let be the importance weight. The two normalized densities give
Since , there is a finite constant such that everywhere. The Independence Metropolis–Hastings algorithm has an accepted transition density satisfying
Consequently the whole state space is a small set, with the one-step minorization condition . Iterating this Doeblin condition gives uniform geometric convergence in total variation distance, so the chain is geometrically ergodic.

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