
theorem
  for F1, F2 being non empty Graph-yielding Function
  for z1 being Element of dom F1, z2 being Element of dom F2
  st F1, F2 are_Disomorphic
  holds canGFDistinction(F1,z1),canGFDistinction(F2,z2) are_Disomorphic
proof
  let F1, F2 be non empty Graph-yielding Function;
  let z1 be Element of dom F1, z2 be Element of dom F2;
  assume A1: F1,F2 are_Disomorphic;
  canGFDistinction(F1,z1), F1 are_Disomorphic by Th105;
  then A2: canGFDistinction(F1,z1), F2 are_Disomorphic by A1, Th40;
  F2, canGFDistinction(F2,z2) are_Disomorphic by Th105;
  hence thesis by A2, Th40;
end;
