let N be non empty with_non-empty_elements set ; :: thesis: for S being non empty stored-program IC-Ins-separated definite realistic steady-programmed standard AMI-Struct of N
for il being Element of NAT
for i being Instruction of S st i is sequential holds
NIC i,il = {(succ il)}

let S be non empty stored-program IC-Ins-separated definite realistic steady-programmed standard AMI-Struct of N; :: thesis: for il being Element of NAT
for i being Instruction of S st i is sequential holds
NIC i,il = {(succ il)}

let il be Element of NAT ; :: thesis: for i being Instruction of S st i is sequential holds
NIC i,il = {(succ il)}

let i be Instruction of S; :: thesis: ( i is sequential implies NIC i,il = {(succ il)} )
assume A1: for s being State of S holds (Exec i,s) . (IC S) = succ (IC s) ; :: according to AMISTD_1:def 16 :: thesis: NIC i,il = {(succ il)}
now
let x be set ; :: thesis: ( x in {(succ il)} iff x in { (IC (Following (ProgramPart ss),ss)) where ss is Element of product the Object-Kind of S : ( IC ss = il & (ProgramPart ss) /. il = i ) } )
A2: now
reconsider il1 = il as Element of ObjectKind (IC S) by COMPOS_1:def 6;
reconsider I = i as Element of the Object-Kind of S . il by COMPOS_1:def 8;
consider t being State of S;
assume A3: x = succ il ; :: thesis: x in { (IC (Following (ProgramPart ss),ss)) where ss is Element of product the Object-Kind of S : ( IC ss = il & (ProgramPart ss) /. il = i ) }
reconsider f = (IC S),il --> il1,I as PartState of S by COMPOS_1:37;
reconsider u = t +* f as Element of product the Object-Kind of S by PBOOLE:155;
A4: dom ((IC S),il --> il1,I) = {(IC S),il} by FUNCT_4:65;
then X: il in dom ((IC S),il --> il1,I) by TARSKI:def 2;
A5: (ProgramPart u) /. il = u . il by COMPOS_1:38
.= ((IC S),il --> il1,I) . il by X, FUNCT_4:14
.= i by FUNCT_4:66 ;
IC S in dom ((IC S),il --> il1,I) by A4, TARSKI:def 2;
then A6: IC u = ((IC S),il --> il1,I) . (IC S) by FUNCT_4:14
.= il by COMPOS_1:3, FUNCT_4:66 ;
then IC (Following (ProgramPart u),u) = succ il by A1, A5;
hence x in { (IC (Following (ProgramPart ss),ss)) where ss is Element of product the Object-Kind of S : ( IC ss = il & (ProgramPart ss) /. il = i ) } by A3, A6, A5; :: thesis: verum
end;
now
assume x in { (IC (Following (ProgramPart ss),ss)) where ss is Element of product the Object-Kind of S : ( IC ss = il & (ProgramPart ss) /. il = i ) } ; :: thesis: x = succ il
then ex s being Element of product the Object-Kind of S st
( x = IC (Following (ProgramPart s),s) & IC s = il & (ProgramPart s) /. il = i ) ;
hence x = succ il by A1; :: thesis: verum
end;
hence ( x in {(succ il)} iff x in { (IC (Following (ProgramPart ss),ss)) where ss is Element of product the Object-Kind of S : ( IC ss = il & (ProgramPart ss) /. il = i ) } ) by A2, TARSKI:def 1; :: thesis: verum
end;
hence NIC i,il = {(succ il)} by TARSKI:2; :: thesis: verum