reserve MS for satisfying_equiv MusicStruct;
reserve a,b,c,d,e,f for Element of MS;

theorem
  MS is non empty implies
  the Equidistance of MS is reflexive &
  field the Equidistance of MS = [:the carrier of MS,the carrier of MS:]
  proof
    assume
A1: MS is non empty;
    the Equidistance of MS is_reflexive_in
      [:the carrier of MS,the carrier of MS:] by Th25;
    hence thesis by A1,PARTIT_2:21;
  end;
