theorem
  for i being Instruction of STC N holds i is jump-only
proof
  let i be Instruction of STC N;
  set M = STC N;
  let s be State of M, o be Object of M, I be Instruction of M such that
  InsCode I = InsCode i and
A1: o in Data-Locations M;
A2: IC M = 0 by Def7;
  Data-Locations M = ({0}) \ ({0}) by A2,Def7
       .= {} by XBOOLE_1:37;
   hence thesis by A1;
end;
