Editing Glossary of graph theory (section)

==N==
{{glossary}}

{{term|N|''N''}}
{{defn|no=1|For the notation for open and closed neighborhoods, see {{gli|neighbourhood}}.}}
{{defn|no=2|A lower-case {{mvar|n}} is often used (especially in computer science) to denote the number of vertices in a given graph.}}

{{term|neighbor}}
{{term|neighbour|multi=y}}
{{defn|A vertex that is adjacent to a given vertex.}}

{{term|neighborhood}}
{{term|neighbourhood|multi=y}}
{{defn|The [[neighbourhood (graph theory)|open neighbourhood]] (or neighborhood) of a vertex {{mvar|v}} is the subgraph induced by all vertices that are adjacent to {{mvar|v}}. The closed neighbourhood is defined in the same way but also includes {{mvar|v}} itself. The open neighborhood of {{mvar|v}} in {{mvar|G}} may be denoted {{math|''N''<sub>''G''</sub>(''v'')}} or {{math|''N''(''v'')}}, and the closed neighborhood may be denoted {{math|''N''<sub>''G''</sub>[''v'']}} or {{math|''N''[''v'']}}. When the openness or closedness of a neighborhood is not specified, it is assumed to be open.}}

{{term|network}}
{{defn|A graph in which attributes (e.g. names) are associated with the nodes and/or edges.}}

{{term|node}}
{{defn|A synonym for {{gli|vertex}}.}}

{{term|non-edge}}
{{defn|A non-edge or anti-edge is a pair of vertices that are not adjacent; the edges of the complement graph.}}

{{term|null graph}}
{{defn|See {{gli|empty graph}}.}}

{{glossary end}}