let w1, w2 be BinOp of (Funcs (X, the carrier of L)); ( ( for f, g being Function of X,L holds w1 . (f,g) = f '+' g ) & ( for f, g being Function of X,L holds w2 . (f,g) = f '+' g ) implies w1 = w2 )
assume that
A1:
for f, g being Function of X,L holds w1 . (f,g) = f '+' g
and
A2:
for f, g being Function of X,L holds w2 . (f,g) = f '+' g
; w1 = w2
now for o being object st o in [:(Funcs (X, the carrier of L)),(Funcs (X, the carrier of L)):] holds
w1 . o = w2 . olet o be
object ;
( o in [:(Funcs (X, the carrier of L)),(Funcs (X, the carrier of L)):] implies w1 . o = w2 . o )assume
o in [:(Funcs (X, the carrier of L)),(Funcs (X, the carrier of L)):]
;
w1 . o = w2 . othen consider u,
v being
object such that A3:
(
u in Funcs (
X, the
carrier of
L) &
v in Funcs (
X, the
carrier of
L) &
o = [u,v] )
by ZFMISC_1:def 2;
reconsider u =
u,
v =
v as
Function of
X, the
carrier of
L by A3, FUNCT_2:66;
w1 . (
u,
v) =
u '+' v
by A1
.=
w2 . (
u,
v)
by A2
;
hence
w1 . o = w2 . o
by A3;
verum end;
hence
w1 = w2
by FUNCT_2:12; verum