let f1, f2 be BinOp of REAL ; :: thesis: ( ( for x, y being Real holds f1 . x,y = min x,y ) & ( for x, y being Real holds f2 . x,y = min x,y ) implies f1 = f2 )
assume that
A1:
for x, y being Real holds f1 . x,y = min x,y
and
A2:
for x, y being Real holds f2 . x,y = min x,y
; :: thesis: f1 = f2
for x, y being Element of REAL holds f1 . x,y = f2 . x,y
proof
let x,
y be
Element of
REAL ;
:: thesis: f1 . x,y = f2 . x,y
(
f1 . x,
y = min x,
y &
f2 . x,
y = min x,
y )
by A1, A2;
hence
f1 . x,
y = f2 . x,
y
;
:: thesis: verum
end;
hence
f1 = f2
by BINOP_1:2; :: thesis: verum