set SAt = Start-At (0,SCM+FSA);
let I be Program of SCM+FSA; ( I is parahalting iff for s being State of SCM+FSA
for P being the Instructions of SCM+FSA -valued ManySortedSet of NAT holds I is_halting_on s,P )
thus
( I is parahalting implies for s being State of SCM+FSA
for P being the Instructions of SCM+FSA -valued ManySortedSet of NAT holds I is_halting_on s,P )
( ( for s being State of SCM+FSA
for P being the Instructions of SCM+FSA -valued ManySortedSet of NAT holds I is_halting_on s,P ) implies I is parahalting )
assume A4:
for s being State of SCM+FSA
for P being the Instructions of SCM+FSA -valued ManySortedSet of NAT holds I is_halting_on s,P
; I is parahalting
let s be State of SCM+FSA; SCMFSA6B:def 3 ( not Start-At (0,SCM+FSA) c= s or for b1 being set holds
( not I c= b1 or b1 halts_on s ) )
assume A5:
Start-At (0,SCM+FSA) c= s
; for b1 being set holds
( not I c= b1 or b1 halts_on s )
let P be the Instructions of SCM+FSA -valued ManySortedSet of NAT ; ( not I c= P or P halts_on s )
assume A6:
I c= P
; P halts_on s
A7:
P = P +* I
by A6, FUNCT_4:103, FUNCT_4:104;
A8:
Initialize s = s
by A5, FUNCT_4:103, FUNCT_4:104;
I is_halting_on s,P
by A4;
hence
P halts_on s
by A7, A8, Def8; verum