reserve AFV for WeakAffVect;
reserve a,b,c,d,e,f,a9,b9,c9,d9,f9,p,q,r,o,x99 for Element of AFV;

theorem Th35:
  Mid a,b,c iff Mid PSym(p,a),PSym(p,b),PSym(p,c)
by Th33;
