%0 Journal Article
%T Less than one implies zero
%A Felix Schwenninger
%A Hans Zwart
%J Mathematics
%D 2013
%I arXiv
%X In this paper we show that from the estimate $\sup_{t \geq 0}\|C(t) - \cos(at)I\| <1$ we can conclude that $C(t)$ equals $\cos(at) I$. Here $\left(C(t)\right)_{t \geq 0}$ is a strongly continuous cosine family on a Banach space.
%U http://arxiv.org/abs/1310.6202v2