Hypergraphs

frame|An example of an undirected hypergraph, with X = \{v_1, v_2, v_3, v_4, v_5, v_6, v_7\} and E = \{e_1,e_2,e_3,e_4\} = \{\{v_1, v_2, v_3\}, \{v_2,v_3\}, \{v_3,v_5,v_6\}, \{v_4\}\}. This hypergraph has order 7 and size 4. Here, edges do not just connect two vertices but several, and are represented by colors. alt=PAOH visualization of a hypergraph|thumb|Alternative representation of the hypergraph reported in the figure above, called PAOH. Edges are vertical lines connecting vertices. V7 is an isolated vertex. Vertices are aligned to the left. The legend on the right shows the names of the

abstract data type in computer science

geometric concept of a 2D space with a "point at infinity" adjoined

theorem

a set of orthonormal bases, where each vector of a given basis has the same overlap with all the vectors of other bases

describing a family of graphs by excluding certain (sub)graphs