let s be State of SCM+FSA; for I being Program of SCM+FSA holds
( Initialized I is_closed_on s iff I is_closed_on Initialized s )
let I be Program of SCM+FSA; ( Initialized I is_closed_on s iff I is_closed_on Initialized s )
hereby ( I is_closed_on Initialized s implies Initialized I is_closed_on s )
assume A1:
Initialized I is_closed_on s
;
I is_closed_on Initialized snow let k be
Element of
NAT ;
IC (Comput ((ProgramPart ((Initialized s) +* (I +* (Start-At (0,SCM+FSA))))),((Initialized s) +* (I +* (Start-At (0,SCM+FSA)))),k)) in dom IX:
s +* ((Initialized I) +* (Start-At (0,SCM+FSA))) = (Initialized s) +* (I +* (Start-At (0,SCM+FSA)))
by Th16;
IC (Comput ((ProgramPart (s +* ((Initialized I) +* (Start-At (0,SCM+FSA))))),(s +* ((Initialized I) +* (Start-At (0,SCM+FSA)))),k)) in dom (Initialized I)
by A1, SCMFSA7B:def 7;
then
IC (Comput ((ProgramPart ((Initialized s) +* (I +* (Start-At (0,SCM+FSA))))),((Initialized s) +* (I +* (Start-At (0,SCM+FSA)))),k)) in dom (Initialized I)
by X;
hence
IC (Comput ((ProgramPart ((Initialized s) +* (I +* (Start-At (0,SCM+FSA))))),((Initialized s) +* (I +* (Start-At (0,SCM+FSA)))),k)) in dom I
by Th20;
verum end; hence
I is_closed_on Initialized s
by SCMFSA7B:def 7;
verum
end;
assume A2:
I is_closed_on Initialized s
; Initialized I is_closed_on s
now let k be
Element of
NAT ;
IC (Comput ((ProgramPart (s +* ((Initialized I) +* (Start-At (0,SCM+FSA))))),(s +* ((Initialized I) +* (Start-At (0,SCM+FSA)))),k)) in dom (Initialized I)X:
s +* ((Initialized I) +* (Start-At (0,SCM+FSA))) = (Initialized s) +* (I +* (Start-At (0,SCM+FSA)))
by Th16;
IC (Comput ((ProgramPart ((Initialized s) +* (I +* (Start-At (0,SCM+FSA))))),((Initialized s) +* (I +* (Start-At (0,SCM+FSA)))),k)) in dom I
by A2, SCMFSA7B:def 7;
then
IC (Comput ((ProgramPart ((Initialized s) +* (I +* (Start-At (0,SCM+FSA))))),((Initialized s) +* (I +* (Start-At (0,SCM+FSA)))),k)) in dom (Initialized I)
by Th20;
hence
IC (Comput ((ProgramPart (s +* ((Initialized I) +* (Start-At (0,SCM+FSA))))),(s +* ((Initialized I) +* (Start-At (0,SCM+FSA)))),k)) in dom (Initialized I)
by X;
verum end;
hence
Initialized I is_closed_on s
by SCMFSA7B:def 7; verum