scheme :: AOFA_A00:sch 1
Scheme{ F₁() -> non empty set , F₂() -> V2() ManySortedSet of F₁(), F₃() -> V2() ManySortedSet of F₁(), F₄( object , object , object ) -> set } :

ex f being ManySortedMSSet of F₂(),F₃() st
for s, r being Element of F₁()
for t being Element of F₂() . s holds ((f . s) . t) . r = F₄(s,r,t)

provided

A1: for s, r being Element of F₁()
for t being Element of F₂() . s holds F₄(s,r,t) is Subset of (F₃() . r)