GS theories are generalizations of Lawvere's algebraic theories having explicit operations of sharing and garbage collection of 'interfaces'. They have been used to give functorial semantics to term graph rewriting and (for the static aspects) to concurrent and mobility calculi (like asynchronous pi-calculus). A higher order extension of them, called GS-Lambda theories, will be introduced and through a toy example it will be showed how they can be used to encode hyperedge replacement graph rewriting. A discussion about its significance and its possible applications in coordination (the latter part being work in progress) might follow.