Weak commutation relations of unbounded operators:Nonlinear extensions

We continue our analysis of the consequences of the commutation relation [S, T ]= 1, where S and T are two closable unbounded operators. The weak sense of thiscommutator is given in terms of the inner product of the Hilbert space H, wherethe operators act. We also consider what we call, adopting a physical terminology, anonlinear extension of the above commutation relations. C