let n be Nat; for L being non empty unital doubleLoopStr holds
( ((0_. L) +* ((0,n) --> ((1. L),(1. L)))) . 0 = 1. L & ((0_. L) +* ((0,n) --> ((1. L),(1. L)))) . n = 1. L )
let L be non empty unital doubleLoopStr ; ( ((0_. L) +* ((0,n) --> ((1. L),(1. L)))) . 0 = 1. L & ((0_. L) +* ((0,n) --> ((1. L),(1. L)))) . n = 1. L )
set t = (0_. L) +* ((0,n) --> ((1. L),(1. L)));
set f = (0,n) --> ((1. L),(1. L));
A3:
dom (0_. L) = NAT
by FUNCT_2:def 1;
A4:
for u being object st u in {0,n} holds
u in NAT
by ORDINAL1:def 12;
A7:
dom ((0,n) --> ((1. L),(1. L))) = {0,n}
by FUNCT_4:62;
then A5:
(dom (0_. L)) \/ (dom ((0,n) --> ((1. L),(1. L)))) = NAT
by A3, A4, TARSKI:def 3, XBOOLE_1:12;
( n in dom ((0,n) --> ((1. L),(1. L))) & n in (dom (0_. L)) \/ (dom ((0,n) --> ((1. L),(1. L)))) )
by A5, A7, TARSKI:def 2, ORDINAL1:def 12;
then A10: ((0_. L) +* ((0,n) --> ((1. L),(1. L)))) . n =
((0,n) --> ((1. L),(1. L))) . n
by FUNCT_4:def 1
.=
1. L
by FUNCT_4:63
;
per cases
( n = 0 or n <> 0 )
;
suppose A6:
n <> 0
;
( ((0_. L) +* ((0,n) --> ((1. L),(1. L)))) . 0 = 1. L & ((0_. L) +* ((0,n) --> ((1. L),(1. L)))) . n = 1. L )
0 in dom ((0,n) --> ((1. L),(1. L)))
by A7, TARSKI:def 2;
hence ((0_. L) +* ((0,n) --> ((1. L),(1. L)))) . 0 =
((0,n) --> ((1. L),(1. L))) . 0
by A5, FUNCT_4:def 1
.=
1. L
by A6, FUNCT_4:63
;
((0_. L) +* ((0,n) --> ((1. L),(1. L)))) . n = 1. Lthus
((0_. L) +* ((0,n) --> ((1. L),(1. L)))) . n = 1. L
by A10;
verum end; end;