theorem :: JGRAPH_7:85

for p1, p2, p3, p4 being Point of (TOP-REAL 2)
for a, b, c, d being Real
for P, Q being Subset of (TOP-REAL 2) st a < b & c < d & p1 `1 = a & p2 `1 = a & p3 `1 = b & p4 `2 = c & c <= p1 `2 & p1 `2 < p2 `2 & p2 `2 <= d & c <= p3 `2 & p3 `2 <= d & a < p4 `1 & p4 `1 <= b & P is_an_arc_of p1,p3 & Q is_an_arc_of p2,p4 & P c= closed_inside_of_rectangle (a,b,c,d) & Q c= closed_inside_of_rectangle (a,b,c,d) holds
P meets Q