Poincaré inequality in probability theory (source code)

= Poincaré inequality in probability theory

A <probability distribution> $\mu$ has <Poincaré inequality in probability theory>[Poincaré constant] $C_P$ when every sufficiently regular $f$ satisfies
$$
\operatorname{Var}_\mu f\leq C_P\int\lVert\nabla f\rVert^2d\mu.
$$