set I = (0,1) --> (i,(halt S));
A1:
dom ((0,1) --> (i,(halt S))) = {0,1}
by FUNCT_4:65;
A6:
(0,1) --> (i,(halt S)) is initial
proof
let m,
n be
Nat;
AFINSQ_1:def 13 ( not n in proj1 ((0,1) --> (i,(halt S))) or n <= m or m in proj1 ((0,1) --> (i,(halt S))) )
assume that A7:
n in dom ((0,1) --> (i,(halt S)))
and A8:
m < n
;
m in proj1 ((0,1) --> (i,(halt S)))
(
n = 0 or
n = 1 )
by A1, A7, TARSKI:def 2;
then
n = 0 + 1
by A8;
then
m <= 0
by A8, NAT_1:13;
then
m = 0
;
hence
m in proj1 ((0,1) --> (i,(halt S)))
by A1, TARSKI:def 2;
verum
end;
thus
(0,1) --> (i,(halt S)) is Program of S
by A6; verum