let m be Nat; modSeq (m,0) = NAT --> 0
set fm = modSeq (m,0);
A1:
for x being object st x in dom (modSeq (m,0)) holds
(modSeq (m,0)) . x = (NAT --> 0) . x
proof
defpred S1[
Nat]
means (modSeq (m,0)) . $1
= 0 ;
let x be
object ;
( x in dom (modSeq (m,0)) implies (modSeq (m,0)) . x = (NAT --> 0) . x )
assume
x in dom (modSeq (m,0))
;
(modSeq (m,0)) . x = (NAT --> 0) . x
then reconsider x =
x as
Element of
NAT ;
(modSeq (m,0)) . 0 =
m mod 0
by Def1
.=
0
;
then A2:
S1[
0 ]
;
A3:
for
n being
Nat st
S1[
n] holds
S1[
n + 1]
by Th14, NAT_1:11;
for
n being
Nat holds
S1[
n]
from NAT_1:sch 2(A2, A3);
then
(modSeq (m,0)) . x = 0
;
hence
(modSeq (m,0)) . x = (NAT --> 0) . x
by FUNCOP_1:7;
verum
end;
dom (modSeq (m,0)) = NAT
by FUNCT_2:def 1;
hence
modSeq (m,0) = NAT --> 0
by A1; verum