for D being non empty set
for d being Element of D
for F being BinOp of D
for i, j being Nat st F is commutative & F is associative & ( ( i >= 1 & j >= 1 ) or F is having_a_unity ) holds
F "**" ((i * j) |-> d) = F "**" (j |-> (F "**" (i |-> d)))