Almost-sure subsequence from convergence in probability (source code)

= Almost-sure subsequence from convergence in probability

From $X_n\to X$ in probability, choose $n_k$ with
$\mathbb P(|X_{n_k}-X|>2^{-k})<2^{-k}$. The first Borel--Cantelli lemma then gives $X_{n_k}\to X$ almost surely.