In the present paper we present an elcmentary proof of the fact that every twoparaneter
strongly continuous semi-group of contractions has a strongly continuous unitary dilation …

Local semigroups of contractions and some applications to Fourier representation theorems
Page 1 Integral Equations and Operator Theory Vol. i0 (1987) 0378-620X/87/060780-2251.50+0.20/0 …

The theory of one-parameter groups of unitary operators in Hilbert Space due to
Stone'shows that to such a group there corresponds a selfadjoint operator which is the …

A short new proof that every continuous semi‐group of subnormal operators in a Hilbert
space may be extended to a continuous semi‐group of normal operators in a larger Hilbert …

There are several known theorems giving sufficient conditions that a multiplicative
semigroup of finite matrices can be simultaneously triangularized. Kaplan-sky's Theorem …

Let f be a unit vector and T={T (t)= etA: t≥ 0} be a (C0) contraction semigroup generated by
A on a complex Hilbert space X. If|< T (t) f, f>|→ 1 as t→∞ then f is an eigenvector of A …

We show that the set of unitary operators on a separable infinite-dimensional Hilbert space
is residual (for the weak operator topology) in the set of all contractions. The same holds for …

In this note we discuss the integral representation of a semi-group of unbounded normal
operators. The result for a semi-group of bounded normal operators can be found in Sz …

HEYDAR RADJAVI Depar− t ment of Mathematics, Dalhousie University Halifax, Nova
Scotia, Canada B 3 H 3 J 5 E-mail: radjavi@ cs. dal. ca 0. Introduction. Let E be a complex …

A notion of two-parameter local semigroups of isometric operators in Hilbert space is
discussed. It is shown that under certain conditions such a semigroup can be extended to a …