Abstract
We formalize in Isabelle/HOL a result
due to S. Banach and H. Steinhaus known as
the Banach-Steinhaus theorem or Uniform boundedness principle: a
pointwise-bounded family of continuous linear operators from a Banach
space to a normed space is uniformly bounded. Our approach is an
adaptation to Isabelle/HOL of a proof due to A. Sokal.