The occurrence of an operation does not characterize the sense of a proposition.
For an operation does not assert anything; only its result does, and this depends on the bases of the operation.
(Operation and function must not be confused with one another.)
5.251 A function cannot be its own argument, but the result of an operation can be its own basis.
5.252 (3) Only in this way is the progress from term to term in a formal series possible (from type to type in the hierarchy of Russell and Whitehead). (Russell and Whitehead have not admitted the possibility of this progress but have made use of it all the same.)
5.253 One operation can reverse the effect of another. Operations can cancel one another.
5.254 Operations can vanish (e.g. denial in "~~p". ~~p = p).