consider X being non empty set such that

A1: proj2 SCM-Instr c= X * by FINSEQ_1:85;

take X ; :: according to COMPOS_0:def 1 :: thesis: SCM-Instr c= [:NAT,(NAT *),(X *):]

A2: SCM-Instr c= [:NAT,(NAT *),(proj2 SCM-Instr):] by Th8;

[:NAT,(NAT *),(proj2 SCM-Instr):] c= [:NAT,(NAT *),(X *):] by A1, MCART_1:73;

hence SCM-Instr c= [:NAT,(NAT *),(X *):] by A2; :: thesis: verum

A1: proj2 SCM-Instr c= X * by FINSEQ_1:85;

take X ; :: according to COMPOS_0:def 1 :: thesis: SCM-Instr c= [:NAT,(NAT *),(X *):]

A2: SCM-Instr c= [:NAT,(NAT *),(proj2 SCM-Instr):] by Th8;

[:NAT,(NAT *),(proj2 SCM-Instr):] c= [:NAT,(NAT *),(X *):] by A1, MCART_1:73;

hence SCM-Instr c= [:NAT,(NAT *),(X *):] by A2; :: thesis: verum