for p1, p2, p3 being Point of (TOP-REAL 2)
for a, b, r being Real st p1 in circle (a,b,r) & p2 in circle (a,b,r) & p3 in circle (a,b,r) & angle (p1,p2,p3) = 0 & p1 <> p2 & p2 <> p3 holds
p1 = p3