:: deftheorem Def4 defines multemb RING_EMB:def 4 :
for A being Ring
for X being non empty set
for f being Function of A,X
for b₄ being BinOp of X holds
( b₄ = multemb f iff for a, b being Element of X holds b₄ . (a,b) = multemb (f,a,b) );