+ Binary operations and properties examples:
+
+ >>> square2 = Le(1, x) & Le(x, 3) & Le(1, y) & Le(y, 3)
+ >>> #test equality
+ >>> square1 == square2
+ False
+ >>> # compute the union of two polyhedrons
+ >>> square1 | square2
+ Or(And(Ge(x, 0), Ge(-x + 2, 0), Ge(y, 0), Ge(-y + 2, 0)), \
+ And(Ge(x - 1, 0), Ge(-x + 3, 0), Ge(y - 1, 0), Ge(-y + 3, 0)))
+ >>> # check if square1 and square2 are disjoint
+ >>> square1.disjoint(square2)
+ False
+ >>> # compute the intersection of two polyhedrons
+ >>> square1 & square2
+ And(Ge(x - 1, 0), Ge(-x + 2, 0), Ge(y - 1, 0), Ge(-y + 2, 0))
+ >>> # compute the convex union of two polyhedrons
+ >>> Polyhedron(square1 | sqaure2)
+ And(Ge(x, 0), Ge(y, 0), Ge(-y + 3, 0), Ge(-x + 3, 0), \
+ Ge(x - y + 2, 0), Ge(-x + y + 2, 0))
+
+ Unary operation and properties examples:
+