Kallman–Rota inequality

In mathematics, the Kallman–Rota inequality, introduced by, is a generalization of the Landau–Kolmogorov inequality to Banach spaces. It states that if A is the infinitesimal generator of a one-parameter contraction semigroup then


 * $$ \|Af\|^2 \le 4\|f\|\|A^2f\|. $$