let N be non empty with_zero set ; for S being non empty with_non-empty_values IC-Ins-separated halting AMI-Struct over N
for P being Instruction-Sequence of S
for s being State of S holds
( P halts_on s iff ex k being Nat st CurInstr (P,(Comput (P,s,k))) = halt S )
let S be non empty with_non-empty_values IC-Ins-separated halting AMI-Struct over N; for P being Instruction-Sequence of S
for s being State of S holds
( P halts_on s iff ex k being Nat st CurInstr (P,(Comput (P,s,k))) = halt S )
let P be Instruction-Sequence of S; for s being State of S holds
( P halts_on s iff ex k being Nat st CurInstr (P,(Comput (P,s,k))) = halt S )
let s be State of S; ( P halts_on s iff ex k being Nat st CurInstr (P,(Comput (P,s,k))) = halt S )
thus
( P halts_on s implies ex k being Nat st CurInstr (P,(Comput (P,s,k))) = halt S )
; ( ex k being Nat st CurInstr (P,(Comput (P,s,k))) = halt S implies P halts_on s )
given k being Nat such that A1:
CurInstr (P,(Comput (P,s,k))) = halt S
; P halts_on s
take
k
; EXTPRO_1:def 8 ( IC (Comput (P,s,k)) in dom P & CurInstr (P,(Comput (P,s,k))) = halt S )
IC (Comput (P,s,k)) in NAT
;
hence
IC (Comput (P,s,k)) in dom P
by PARTFUN1:def 2; CurInstr (P,(Comput (P,s,k))) = halt S
thus
CurInstr (P,(Comput (P,s,k))) = halt S
by A1; verum