Q:

Math vocab: operator on $S$ and into $S =$?

Is there a special name for a binary operation on the set $S$ that is also into $S$, that is unambiguous with other uses.  I.e.  if it's "operator on $S$", I've heard that in other places meaning the operator could map to another set $T$.  I'm working on a math library in the D language.

A:

Are you looking for the term closed binary operation? (other reference)

