A short proof of the zero-two law for cosine functions
Language
en
Article de revue
This item was published in
Archiv der Mathematik. 2015-10, vol. 105, n° 4, p. 381-387
Springer Verlag
English Abstract
Let $(C(t))_{t\in \R}$ be a cosine function in a unital Banach algebra. We give a simple proof of the fact that if lim sup$_{t\to 0}\Vert C(t)-1_A\Vert<2,$ then lim sup$_{t\to 0}\Vert C(t)-1_A\Vert=0.$
Let $(C(t))_{t\in \R}$ be a cosine function in a unital Banach algebra. We give a simple proof of the fact that if lim sup$_{t\to 0}\Vert C(t)-1_A\Vert<2,$ then lim sup$_{t\to 0}\Vert C(t)-1_A\Vert=0.$Read less <
English Keywords
47D09
Secondary 26A99
commutative local Banach algebra AMS classification : Primary 46J45
Cosine function
scalar cosine function
Origin
Hal imported