take 1 ; :: according to AMISTD_2:def 12 :: thesis: ( 1 in dom (AddressPart (a =0_goto i1)) & (product" (AddressParts (InsCode (a =0_goto i1)))) . 1 = NAT )
dom (AddressPart (a =0_goto i1)) = dom <*i1,a*> by MCART_1:def 2
.= {1,2} by FINSEQ_1:4, FINSEQ_3:29 ;
hence 1 in dom (AddressPart (a =0_goto i1)) by TARSKI:def 2; :: thesis: (product" (AddressParts (InsCode (a =0_goto i1)))) . 1 = NAT
thus (product" (AddressParts (InsCode (a =0_goto i1)))) . 1 = NAT by Th51; :: thesis: verum