for D being non empty set
for F, G being XFinSequence of D
for b being BinOp of D
for bFG being XFinSequence of D st b is commutative & b is associative & ( b is having_a_unity or len F >= 1 ) & len F = len G & len F = len bFG & ( for n being Nat st n in dom bFG holds
bFG . n = b . ((F . n),(G . n)) ) holds
b "**" (F ^ G) = b "**" bFG