let D be non empty set ; for e being Element of D
for F, G being BinOp of D st F is associative & F is having_a_unity & F is having_an_inverseOp & G is_distributive_wrt F & e = the_unity_wrt F holds
for d being Element of D holds
( G . (e,d) = e & G . (d,e) = e )
let e be Element of D; for F, G being BinOp of D st F is associative & F is having_a_unity & F is having_an_inverseOp & G is_distributive_wrt F & e = the_unity_wrt F holds
for d being Element of D holds
( G . (e,d) = e & G . (d,e) = e )
let F, G be BinOp of D; ( F is associative & F is having_a_unity & F is having_an_inverseOp & G is_distributive_wrt F & e = the_unity_wrt F implies for d being Element of D holds
( G . (e,d) = e & G . (d,e) = e ) )
assume that
A1:
F is associative
and
A2:
F is having_a_unity
and
A3:
F is having_an_inverseOp
and
A4:
G is_distributive_wrt F
and
A5:
e = the_unity_wrt F
; for d being Element of D holds
( G . (e,d) = e & G . (d,e) = e )
let d be Element of D; ( G . (e,d) = e & G . (d,e) = e )
set ed = G . (e,d);
F . ((G . (e,d)),(G . (e,d))) =
G . ((F . (e,e)),d)
by A4, BINOP_1:11
.=
G . (e,d)
by A2, A5, SETWISEO:15
;
hence
G . (e,d) = e
by A1, A2, A3, A5, Th65; G . (d,e) = e
set de = G . (d,e);
F . ((G . (d,e)),(G . (d,e))) =
G . (d,(F . (e,e)))
by A4, BINOP_1:11
.=
G . (d,e)
by A2, A5, SETWISEO:15
;
hence
G . (d,e) = e
by A1, A2, A3, A5, Th65; verum