let F be NAT -defined the Instructions of SCM -valued total Function; ( <%(AddTo ((dl. 0),(dl. 1)))%> ^ <%(halt SCM)%> c= F implies for i1, i2 being Integer
for s being 0 -started State-consisting of 0 ,<*i1*> ^ <*i2*> holds
( F halts_on s & LifeSpan (F,s) = 1 & (Result (F,s)) . (dl. 0) = i1 + i2 & ( for d being Data-Location st d <> dl. 0 holds
(Result (F,s)) . d = s . d ) ) )
assume Z:
<%(AddTo ((dl. 0),(dl. 1)))%> ^ <%(halt SCM)%> c= F
; for i1, i2 being Integer
for s being 0 -started State-consisting of 0 ,<*i1*> ^ <*i2*> holds
( F halts_on s & LifeSpan (F,s) = 1 & (Result (F,s)) . (dl. 0) = i1 + i2 & ( for d being Data-Location st d <> dl. 0 holds
(Result (F,s)) . d = s . d ) )
let i1, i2 be Integer; for s being 0 -started State-consisting of 0 ,<*i1*> ^ <*i2*> holds
( F halts_on s & LifeSpan (F,s) = 1 & (Result (F,s)) . (dl. 0) = i1 + i2 & ( for d being Data-Location st d <> dl. 0 holds
(Result (F,s)) . d = s . d ) )
let s be 0 -started State-consisting of 0 ,<*i1*> ^ <*i2*>; ( F halts_on s & LifeSpan (F,s) = 1 & (Result (F,s)) . (dl. 0) = i1 + i2 & ( for d being Data-Location st d <> dl. 0 holds
(Result (F,s)) . d = s . d ) )
set s0 = Comput (F,s,0);
set s1 = Comput (F,s,(0 + 1));
A1:
s = Comput (F,s,0)
by EXTPRO_1:3;
A2:
( s . (dl. 0) = i1 & s . (dl. 1) = i2 )
by Th15;
A3:
IC s = 0
by COMPOS_1:def 16;
A4:
F . 0 = AddTo ((dl. 0),(dl. 1))
by Z, Th15A;
then A5:
IC (Comput (F,s,(0 + 1))) = 0 + 1
by A3, A1, Th19;
A6:
F . 1 = halt SCM
by Z, Th15A;
hence
F halts_on s
by A5, EXTPRO_1:31; ( LifeSpan (F,s) = 1 & (Result (F,s)) . (dl. 0) = i1 + i2 & ( for d being Data-Location st d <> dl. 0 holds
(Result (F,s)) . d = s . d ) )
thus
LifeSpan (F,s) = 1
by A3, A6, A1, A5, EXTPRO_1:34; ( (Result (F,s)) . (dl. 0) = i1 + i2 & ( for d being Data-Location st d <> dl. 0 holds
(Result (F,s)) . d = s . d ) )
(Comput (F,s,(0 + 1))) . (dl. 0) = ((Comput (F,s,0)) . (dl. 0)) + ((Comput (F,s,0)) . (dl. 1))
by A3, A4, A1, Th19;
hence
(Result (F,s)) . (dl. 0) = i1 + i2
by A6, A2, A1, A5, EXTPRO_1:32; for d being Data-Location st d <> dl. 0 holds
(Result (F,s)) . d = s . d
let d be Data-Location ; ( d <> dl. 0 implies (Result (F,s)) . d = s . d )
assume A7:
d <> dl. 0
; (Result (F,s)) . d = s . d
thus (Result (F,s)) . d =
(Comput (F,s,(0 + 1))) . d
by A6, A5, EXTPRO_1:32
.=
s . d
by A3, A4, A1, A7, Th19
; verum