theorem Th13: :: BINOP_1:13

for A being non empty set
for o, o9 being BinOp of A st o9 is commutative holds
( o9 is_distributive_wrt o iff for a, b, c being Element of A holds o9 . ((o . (a,b)),c) = o . ((o9 . (a,c)),(o9 . (b,c))) )