theorem Th25:
  for ins being Instruction of SCM+FSA st InsCode ins = 3 holds ex
  da,db st ins = SubFrom(da,db)
proof
  let ins be Instruction of SCM+FSA;
  assume
A1: InsCode ins = 3;
  then reconsider I = ins as Instruction of SCM by Th8;
  consider A,B such that
A2: I = SubFrom(A,B) by A1,AMI_5:10;
A3:   Int-Locations = SCM+FSA-Data-Loc;
  A in SCM-Data-Loc & B in SCM-Data-Loc by AMI_2:def 16;
  then reconsider da = A, db = B as Int-Location by A3;
  take da,db;
  thus thesis by A2,Def8;
end;
