scheme :: MSAFREE4:sch 1
Sch1{ F₁() -> set , F₂() -> non-empty ManySortedSet of F₁(), F₃( object , object ) -> set } :

ex f being ManySortedFunction of F₁() st
for x being set st x in F₁() holds
( dom (f . x) = F₂() . x & ( for y being Element of F₂() . x holds (f . x) . y = F₃(x,y) ) )