let i1, i2 be Integer; :: thesis: for I being Instruction of SCM st I is sequential & I is 0 -dl.constant holds
for P being Instruction-Sequence of SCM st IterativeAlgorithm I c= P holds
for s being 0 -started State-consisting of <%i1,0,i2%> holds
( IC (Comput (P,s,0)) = 0 & ( for k being Nat st k >= 1 holds
IC (Comput (P,s,k)) = 1 ) & ( for k being Nat holds
( (Comput (P,s,k)) . (dl. 0) = i1 & (Comput (P,s,k)) . (dl. 1) = 0 & (Comput (P,s,k)) . (dl. 2) = i2 ) ) & LifeSpan (P,s) = 1 )

let I be Instruction of SCM; :: thesis: ( I is sequential & I is 0 -dl.constant implies for P being Instruction-Sequence of SCM st IterativeAlgorithm I c= P holds
for s being 0 -started State-consisting of <%i1,0,i2%> holds
( IC (Comput (P,s,0)) = 0 & ( for k being Nat st k >= 1 holds
IC (Comput (P,s,k)) = 1 ) & ( for k being Nat holds
( (Comput (P,s,k)) . (dl. 0) = i1 & (Comput (P,s,k)) . (dl. 1) = 0 & (Comput (P,s,k)) . (dl. 2) = i2 ) ) & LifeSpan (P,s) = 1 ) )

assume A1: ( I is sequential & I is 0 -dl.constant ) ; :: thesis: for P being Instruction-Sequence of SCM st IterativeAlgorithm I c= P holds
for s being 0 -started State-consisting of <%i1,0,i2%> holds
( IC (Comput (P,s,0)) = 0 & ( for k being Nat st k >= 1 holds
IC (Comput (P,s,k)) = 1 ) & ( for k being Nat holds
( (Comput (P,s,k)) . (dl. 0) = i1 & (Comput (P,s,k)) . (dl. 1) = 0 & (Comput (P,s,k)) . (dl. 2) = i2 ) ) & LifeSpan (P,s) = 1 )

let P be Instruction-Sequence of SCM; :: thesis: ( IterativeAlgorithm I c= P implies for s being 0 -started State-consisting of <%i1,0,i2%> holds
( IC (Comput (P,s,0)) = 0 & ( for k being Nat st k >= 1 holds
IC (Comput (P,s,k)) = 1 ) & ( for k being Nat holds
( (Comput (P,s,k)) . (dl. 0) = i1 & (Comput (P,s,k)) . (dl. 1) = 0 & (Comput (P,s,k)) . (dl. 2) = i2 ) ) & LifeSpan (P,s) = 1 ) )

assume A2: IterativeAlgorithm I c= P ; :: thesis: for s being 0 -started State-consisting of <%i1,0,i2%> holds
( IC (Comput (P,s,0)) = 0 & ( for k being Nat st k >= 1 holds
IC (Comput (P,s,k)) = 1 ) & ( for k being Nat holds
( (Comput (P,s,k)) . (dl. 0) = i1 & (Comput (P,s,k)) . (dl. 1) = 0 & (Comput (P,s,k)) . (dl. 2) = i2 ) ) & LifeSpan (P,s) = 1 )

let s be 0 -started State-consisting of <%i1,0,i2%>; :: thesis: ( IC (Comput (P,s,0)) = 0 & ( for k being Nat st k >= 1 holds
IC (Comput (P,s,k)) = 1 ) & ( for k being Nat holds
( (Comput (P,s,k)) . (dl. 0) = i1 & (Comput (P,s,k)) . (dl. 1) = 0 & (Comput (P,s,k)) . (dl. 2) = i2 ) ) & LifeSpan (P,s) = 1 )

thus IC (Comput (P,s,0)) = 0 by MEMSTR_0:def 12; :: thesis: ( ( for k being Nat st k >= 1 holds
IC (Comput (P,s,k)) = 1 ) & ( for k being Nat holds
( (Comput (P,s,k)) . (dl. 0) = i1 & (Comput (P,s,k)) . (dl. 1) = 0 & (Comput (P,s,k)) . (dl. 2) = i2 ) ) & LifeSpan (P,s) = 1 )

set s0 = Comput (P,s,0);
set s1 = Comput (P,s,(0 + 1));
A3: IC (Comput (P,s,0)) = 0 by MEMSTR_0:def 12;
A4: (Comput (P,s,0)) . (dl. 1) = 0 by Th14;
A5: (Comput (P,s,0)) . (dl. 2) = i2 by Th14;
A6: IC (Comput (P,s,(0 + 1))) = 1 by A2, A3, A4, Th16;
hereby :: thesis: ( ( for k being Nat holds
( (Comput (P,s,k)) . (dl. 0) = i1 & (Comput (P,s,k)) . (dl. 1) = 0 & (Comput (P,s,k)) . (dl. 2) = i2 ) ) & LifeSpan (P,s) = 1 )
let k be Nat; :: thesis: ( k >= 1 implies IC (Comput (P,s,k)) = 1 )
assume k >= 1 ; :: thesis: IC (Comput (P,s,k)) = 1
then reconsider z = k - 1 as Element of NAT by INT_1:3;
Comput (P,s,(1 + z)) = Comput (P,s,(0 + 1)) by A2, A6, Th18;
hence IC (Comput (P,s,k)) = 1 by A2, A3, A4, Th16; :: thesis: verum
end;
hereby :: thesis: LifeSpan (P,s) = 1
let k be Nat; :: thesis: ( (Comput (P,s,k)) . (dl. 0) = i1 & (Comput (P,s,b1)) . (dl. 1) = 0 & (Comput (P,s,b1)) . (dl. 2) = i2 )
thus (Comput (P,s,k)) . (dl. 0) = i1 by A1, A2, Th26; :: thesis: ( (Comput (P,s,b1)) . (dl. 1) = 0 & (Comput (P,s,b1)) . (dl. 2) = i2 )
per cases ( k = 0 or ex z being Nat st k = z + 1 ) by NAT_1:6;
suppose k = 0 ; :: thesis: ( (Comput (P,s,b1)) . (dl. 1) = 0 & (Comput (P,s,b1)) . (dl. 2) = i2 )
hence ( (Comput (P,s,k)) . (dl. 1) = 0 & (Comput (P,s,k)) . (dl. 2) = i2 ) by Th14; :: thesis: verum
end;
suppose ex z being Nat st k = z + 1 ; :: thesis: ( (Comput (P,s,b1)) . (dl. 1) = 0 & (Comput (P,s,b1)) . (dl. 2) = i2 )
then consider z being Nat such that
A7: k = z + 1 ;
( (Comput (P,s,(0 + 1))) . (dl. 1) = (Comput (P,s,0)) . (dl. 1) & (Comput (P,s,(0 + 1))) . (dl. 2) = (Comput (P,s,0)) . (dl. 2) ) by A2, A3, Th16;
hence ( (Comput (P,s,k)) . (dl. 1) = 0 & (Comput (P,s,k)) . (dl. 2) = i2 ) by A2, A4, A5, A6, A7, Th18; :: thesis: verum
end;
end;
end;
P . 1 = halt SCM by A2, Th8;
hence LifeSpan (P,s) = 1 by A3, A6, EXTPRO_1:33; :: thesis: verum