Theorem (Portmanteau): Let \(g: \real^d \to \real\). The following conditions are equivalent:

(a) \(\x_n \inD \x\).
(b) \(\Ex g(\x_n) \to \Ex g(\x)\) for all continuous functions \(g\) with compact support.
(c) \(\Ex g(\x_n) \to \Ex g(\x)\) for all continuous bounded functions \(g\).
(d) \(\Ex g(\x_n) \to \Ex g(\x)\) for all bounded measurable functions \(g\) such that \(g\) is continuous almost everywhere.

Proof: van der Vaart, Asymptotic Statistics (1998), Lemma 2.2.

The Portmanteau theorem can include several more equivalence conditions; van der Vaart provides seven.