let a, b be Int-Location ; for i being Instruction of SCM+FSA st ( i = a := b or i = AddTo (a,b) or i = SubFrom (a,b) or i = MultBy (a,b) or i = Divide (a,b) ) holds
UsedIntLoc i = {a,b}
let i be Instruction of SCM+FSA; ( ( i = a := b or i = AddTo (a,b) or i = SubFrom (a,b) or i = MultBy (a,b) or i = Divide (a,b) ) implies UsedIntLoc i = {a,b} )
( a in Int-Locations & b in Int-Locations )
by SCMFSA_2:2;
then
{a,b} c= Int-Locations
by ZFMISC_1:32;
then reconsider ab = {a,b} as Element of Fin Int-Locations by FINSUB_1:def 5;
assume A1:
( i = a := b or i = AddTo (a,b) or i = SubFrom (a,b) or i = MultBy (a,b) or i = Divide (a,b) )
; UsedIntLoc i = {a,b}
then
( InsCode i = 1 or InsCode i = 2 or InsCode i = 3 or InsCode i = 4 or InsCode i = 5 )
by SCMFSA_2:18, SCMFSA_2:19, SCMFSA_2:20, SCMFSA_2:21, SCMFSA_2:22;
then
InsCode i in {1,2,3,4,5}
by ENUMSET1:def 3;
then
UsedIntLoc i = ab
by A1, Def1;
hence
UsedIntLoc i = {a,b}
; verum