deffunc H₁( Element of carr f, Element of carr f) -> Element of carr f = multemb (f,$1,$2);
consider F being BinOp of (carr f) such that
A1: for a, b being Element of carr f holds F . (a,b) = H₁(a,b) from BINOP_1:sch 4();
take F ; :: thesis: for a, b being Element of carr f holds F . (a,b) = multemb (f,a,b)
thus for a, b being Element of carr f holds F . (a,b) = multemb (f,a,b) by A1; :: thesis: verum