Semigroup commutation with its unbounded generator
= Semigroup commutation with its unbounded generator
{title2=$T_tD(Z)\subseteq D(Z),\quad ZT_tf=T_tZf$}
For a <strongly continuous semigroup>, apply the bounded operator $T_t$ to the difference quotient defining its <semigroup generator>. The limit proves domain invariance and commutation on the generator domain. This is not an assertion that the unbounded generator acts on every vector.
// Target: analysis.bigb