Discrete geometry
（重定向自Combinatorial geometry）
![A collection of circles and the corresponding unit disk graph](/Images/godic/202501/05/Unit_disk_graph.svg1604.png")
![Graphs are drawn as rods connected by rotating hinges. The cycle graph C4 drawn as a square can be tilted over by the blue force into a parallelogram, so it is a flexible graph. **, drawn as a triangle, cannot be altered by any force that is applied to it, so it is a rigid graph.](/Images/godic/202501/05/Structural_rigidity_basic_examples.svg1604.png")
![Seven points are elements of seven lines in the Fano plane, an example of an incidence structure.](/Images/godic/202501/05/Fano_plane_with_nimber_labels.svg1604.png")
Discrete geometry and combinatorial geometry are branches of geometry that study combinatorial properties and constructive methods of discrete geometric objects. Most questions in discrete geometry involve finite or discrete sets of basic geometric objects, such as points, lines, planes, circles, spheres, polygons, and so forth. The subject focuses on the combinatorial properties of these objects, such as how they intersect one another, or how they may be arranged to cover a larger object.