scheme :: MODELC_1:sch 6
Func2EX{ F₁() -> non empty set , F₂() -> Function of F₁(),BOOLEAN, F₃() -> Function of F₁(),BOOLEAN, F₄( object , Function of F₁(),BOOLEAN, Function of F₁(),BOOLEAN) -> boolean object } :

ex h being set st
( h in ModelSP F₁() & ( for s being set st s in F₁() holds
( F₄(s,F₂(),F₃()) = TRUE iff (Fid (h,F₁())) . s = TRUE ) ) )