A combinator is a lambda term with no free variables. Combinators, as the name suggests, serve only to combine the arguments they are given. In other words:
Every term in the body appears in the head.
or: They are a special class of lambda expressions that can only combine the arguments they are given, without introducing any new values or random data.
A combinator is a lambda term with no free variables. Combinators, as the name suggests, serve only to combine the arguments they are given. In other words: