theorem Th13: :: JORDAN5C:13

for P being Subset of (TOP-REAL 2)
for p1, p2, q1, q2, q3 being Point of (TOP-REAL 2) st LE q1,q2,P,p1,p2 & LE q2,q3,P,p1,p2 holds
LE q1,q3,P,p1,p2