let R be good Ring; :: thesis: for i1, il being Element of NAT holds NIC ((goto (i1,R)),il) = {i1}
let i1, il be Element of NAT ; :: thesis: NIC ((goto (i1,R)),il) = {i1}

now

let x be set ; :: thesis: ( x in {i1} iff x in { (IC (Exec ((goto (i1,R)),s))) where s is Element of product the Object-Kind of (SCM R) : IC s = il } )

A1: now

reconsider il1 = il as Element of ObjectKind (IC ) by MEMSTR_0:def 3;
set I = goto (i1,R);
set t = the State of (SCM R);
set Q = the Instruction-Sequence of (SCM R);
assume A2: x = i1 ; :: thesis: x in { (IC (Exec ((goto (i1,R)),s))) where s is Element of product the Object-Kind of (SCM R) : IC s = il }
reconsider u = the State of (SCM R) +* ((IC ),il1) as Element of product the Object-Kind of (SCM R) by CARD_3:107;
reconsider P = the Instruction-Sequence of (SCM R) +* (il,(goto (i1,R))) as Instruction-Sequence of (SCM R) ;
A3: P /. il = P . il by PBOOLE:143;
IC in dom the State of (SCM R) by MEMSTR_0:2;
then A4: IC u = il by FUNCT_7:31;
il in NAT ;
then il in dom the Instruction-Sequence of (SCM R) by PARTFUN1:def 2;
then B4: P . il = goto (i1,R) by FUNCT_7:31;
then IC (Following (P,u)) = i1 by A4, A3, SCMRING2:15;
hence x in { (IC (Exec ((goto (i1,R)),s))) where s is Element of product the Object-Kind of (SCM R) : IC s = il } by A2, A3, A4, B4; :: thesis: verum

end;

now

assume x in { (IC (Exec ((goto (i1,R)),s))) where s is Element of product the Object-Kind of (SCM R) : IC s = il } ; :: thesis: x = i1
then ex s being Element of product the Object-Kind of (SCM R) st
( x = IC (Exec ((goto (i1,R)),s)) & IC s = il ) ;
hence x = i1 by SCMRING2:15; :: thesis: verum

end;

hence ( x in {i1} iff x in { (IC (Exec ((goto (i1,R)),s))) where s is Element of product the Object-Kind of (SCM R) : IC s = il } ) by A1, TARSKI:def 1; :: thesis: verum

end;

hence NIC ((goto (i1,R)),il) = {i1} by TARSKI:1; :: thesis: verum