:: deftheorem defines R_Segment JORDAN6:def 4 :
for P being Subset of (TOP-REAL 2)
for p1, p2, q1 being Point of (TOP-REAL 2) holds R_Segment (P,p1,p2,q1) = { q where q is Point of (TOP-REAL 2) : LE q1,q,P,p1,p2 } ;