Given A∈ℝnA \in \mathbb{R}^n and compact set Y∈ℝkY \in \mathbb{R}^k, the correspondence f:A→Yf: A \to Y is l.h.c. if for every sequence xm→x∈Ax_m \to x \in A with xm∈Ax^m \in A for all mm, and every y∈f(x)y \in f(x), we can find a sequence ym→yy^m \to y.
lower semicontinuity is a more general form