The optimal bound $e$ in a dyadic version of Uchiyama's Lemma

Abstract

The best known constant in Uchiyama's Lemma is $e$. A conjecture states that this cannot be improved. We show that the constant $e$ also stands in a dyadic version of Uchiyama's Lemma. Further, we prove that in the dyadic case, the constant $e$ can indeed not be improved. We deduce a dyadic version of the reproducing kernel thesis for the embedding theorem.