theorem Th56: :: JGRAPH_6:56

for a, b, c, d being Real
for p1, p2 being Point of (TOP-REAL 2) st a < b & c < d & p1 in LSeg (|[a,d]|,|[b,d]|) & p2 in LSeg (|[a,d]|,|[b,d]|) holds
( LE p1,p2, rectangle (a,b,c,d) iff p1 `1 <= p2 `1 )