reserve R for Ring,
  r for Element of R,
  a, b, d1, d2 for Data-Location of R,
  il, i1, i2 for Nat,
  I for Instruction of SCM R,
  s,s1, s2 for State of SCM R,
  T for InsType of the InstructionsF of SCM R,
  k for Nat;
reserve S for non trivial Ring,
  p, q for Data-Location of S,
  w for Element of S;

theorem
  InsCode I <= 7
proof
  set T = InsCode I;
  T = 0 or T = 1 or T = 2 or T = 3 or T = 4 or T = 5 or T = 6 or T = 7 by Lm2;
  hence thesis;
end;
