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