let I be Instruction of S; ( I is sequential implies I is IC-good )
assume A1:
I is sequential
; I is IC-good
let k be natural number ; AMISTD_2:def 18 for s1 being State of S holds (IC (Exec I,s1)) + k = IC (Exec (IncAddr I,k),(IncrIC s1,k))
let s1 be State of S; (IC (Exec I,s1)) + k = IC (Exec (IncAddr I,k),(IncrIC s1,k))
set s2 = IncrIC s1,k;
dom ((IC S) .--> ((IC s1) + k)) = {(IC S)}
by FUNCOP_1:19;
then
IC S in dom ((IC S) .--> ((IC s1) + k))
by TARSKI:def 1;
then A3: IC (IncrIC s1,k) =
((IC S) .--> ((IC s1) + k)) . (IC S)
by FUNCT_4:14
.=
(IC s1) + k
by FUNCOP_1:87
;
A4: IC (Exec I,(IncrIC s1,k)) =
succ (IC (IncrIC s1,k))
by A1, AMISTD_1:def 16
.=
((IC s1) + 1) + k
by A3
;
IC (Exec I,s1) =
succ (IC s1)
by A1, AMISTD_1:def 16
.=
(IC s1) + 1
;
hence
(IC (Exec I,s1)) + k = IC (Exec (IncAddr I,k),(IncrIC s1,k))
by A1, A4, Th29; verum