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
  Mid a,p,a9 & Mid b,q,b9 & MDist p,q implies a,b // b9,a9
proof
  assume that
A1: Mid a,p,a9 and
A2: Mid b,q,b9 and
A3: MDist p,q;
  Mid a,q,a9 by A1,A3,Th23;
  hence thesis by A2,Th25;
end;
