theorem Th11: :: JORDAN21:11

for P being Subset of the carrier of (TOP-REAL 2)
for p1, p2, q1, q2 being Point of (TOP-REAL 2) st P is_an_arc_of p1,p2 & p1 <> q1 & p2 <> q2 holds
( not p1 in Segment (P,p1,p2,q1,q2) & not p2 in Segment (P,p1,p2,q1,q2) )