In geometry, a double wedge is the (closure of) the symmetric difference of two half-spaces whose boundaries are not parallel to each other. For instance, in the Cartesian plane, the union of the positive and negative quadrants forms a double wedge, and more generally in two dimensions a double wedge consists of the set of points within two vertical angles defined by a pair of lines.. In projective geometry double wedges are the projective duals of line segments.
- de Berg, Mark; Cheong, Otfried; van Kreveld, Marc; Overmars, Mark (2008), Computational Geometry: Algorithms and Applications (3rd ed.), Springer, p. 178, ISBN 9783540779735.