reserve r for Real;
reserve a, b for Real;
reserve T for non empty TopSpace;
reserve A for non empty SubSpace of T;
reserve P,Q for Subset of T,
  p for Point of T;
reserve M for non empty MetrSpace,
  p for Point of M;
reserve A for non empty SubSpace of M;
reserve F,G for Subset-Family of M;

theorem Th11:
  for p,q being Point of RealSpace, x,y being Real holds x=
  p & y=q implies dist(p,q) = |.x-y.|
   by METRIC_1:def 12;
