A remark on contraction semigroups on Banach spaces

P. K. Lin

Let $X$ be a complex Banach space and let $J:X\to X^{\ast }$ be a duality section on $X$ (i.e. $⟨x,J(x)⟩=\Vert J(x)\Vert \Vert x\Vert =\Vert J(x){\Vert }^2=\Vert x{\Vert }^2$). For any unit vector $x$ and any…