let s be State of SCM+FSA ; for J being Program of SCM+FSA
for Ig being good Program of SCM+FSA
for f being FinSeq-Location st ( Ig is parahalting or ( Ig is_halting_on Initialize s & Ig is_closed_on Initialize s ) ) & ( J is parahalting or ( J is_halting_on IExec Ig,s & J is_closed_on IExec Ig,s ) ) holds
(IExec (Ig ';' J),s) . f = (IExec J,(IExec Ig,s)) . f
let J be Program of SCM+FSA ; for Ig being good Program of SCM+FSA
for f being FinSeq-Location st ( Ig is parahalting or ( Ig is_halting_on Initialize s & Ig is_closed_on Initialize s ) ) & ( J is parahalting or ( J is_halting_on IExec Ig,s & J is_closed_on IExec Ig,s ) ) holds
(IExec (Ig ';' J),s) . f = (IExec J,(IExec Ig,s)) . f
let Ig be good Program of SCM+FSA ; for f being FinSeq-Location st ( Ig is parahalting or ( Ig is_halting_on Initialize s & Ig is_closed_on Initialize s ) ) & ( J is parahalting or ( J is_halting_on IExec Ig,s & J is_closed_on IExec Ig,s ) ) holds
(IExec (Ig ';' J),s) . f = (IExec J,(IExec Ig,s)) . f
let f be FinSeq-Location ; ( ( Ig is parahalting or ( Ig is_halting_on Initialize s & Ig is_closed_on Initialize s ) ) & ( J is parahalting or ( J is_halting_on IExec Ig,s & J is_closed_on IExec Ig,s ) ) implies (IExec (Ig ';' J),s) . f = (IExec J,(IExec Ig,s)) . f )
set I = Ig;
assume that
A1:
( Ig is parahalting or ( Ig is_halting_on Initialize s & Ig is_closed_on Initialize s ) )
and
A2:
( J is parahalting or ( J is_halting_on IExec Ig,s & J is_closed_on IExec Ig,s ) )
; (IExec (Ig ';' J),s) . f = (IExec J,(IExec Ig,s)) . f
A3:
J is_halting_on IExec Ig,s
by A2, SCMFSA7B:25;
A4:
Ig is_closed_on Initialize s
by A1, SCMFSA7B:24;
A5:
not f in dom (Start-At ((IC (IExec J,(IExec Ig,s))) + (card Ig)),SCM+FSA )
by SCMFSA6B:10;
A6:
J is_closed_on IExec Ig,s
by A2, SCMFSA7B:24;
Ig is_halting_on Initialize s
by A1, SCMFSA7B:25;
then
IExec (Ig ';' J),s = (IExec J,(IExec Ig,s)) +* (Start-At ((IC (IExec J,(IExec Ig,s))) + (card Ig)),SCM+FSA )
by A3, A4, A6, Th7;
hence
(IExec (Ig ';' J),s) . f = (IExec J,(IExec Ig,s)) . f
by A5, FUNCT_4:12; verum