Schost's transform

Here is its definition : TS(f)=f+Id

Id being of course the identity

The k-operator of Schost

He's simply defined by : Sk(f)=f+k.Id

These operators have a lot of proprieties. As an example, their inverse are very simple : Inv(Sk)=S(-k).

It's another name for the 0-operator of Schost.

It has a surprising amount of proprieties...