Talk:Evolution operator

Parameter space

It seems that the parameters $t,s$ are usually taken to lie in some subset of the reals. The condition "If $t,s$ belong to an infinite-dimensional space" seems incorrect, and I have replaced it with the anodyne "Under some circumstances" which is consistent with the reference [a1]. Richard Pinch (talk) 20:45, 16 October 2017 (CEST)

Yes. Looking at the corresponding article in Russian I do not understand, wherefrom came this strange phrase.

In addition, "linear operator-function of $t$ and $s$" may seem to mean linearity in $(s,t)$ (while the operators need not be linear). But of course, the true meaning is a (nonlinear) map from $(s,t)$ to linear operators. Boris Tsirelson (talk) 22:22, 16 October 2017 (CEST)