Content deleted Content added
it's important in the definition of a 2-factor for the cycles not to overlap |
|||
Line 3:
[[Image:Desargues graph 3color edge.svg|thumb|200px|1-factorization of the [[Desargues graph]]: each color class is a {{nowrap|1-factor}}.]]
[[Image:Petersen-graph-factors.svg|right|thumb|200px|The [[Petersen graph]] can be partitioned into a {{nowrap|1-factor}} (red) and a {{nowrap|2-factor}} (blue). However, the graph is not {{nowrap|1-factorable}}.]]
In [[graph theory]], a '''factor''' of a [[graph (discrete mathematics)|graph]] ''G'' is a [[spanning subgraph]], i.e., a subgraph that has the same vertex set as ''G''. A '''''k''-factor''' of a graph is a spanning ''k''-[[Regular graph|regular]] subgraph, and a '''''k''-factorization''' partitions the edges of the graph into disjoint ''k''-factors. A graph ''G'' is said to be '''''k''-factorable''' if it admits a ''k''-factorization. In particular, a '''1-factor''' is a [[perfect matching]], and a 1-factorization of a ''k''-regular graph is a [[edge coloring|proper edge coloring]] with ''k'' colors. A '''2-factor''' is a collection of disjoint [[cycle (graph theory)|cycle]]s that spans all vertices of the graph.
==1-factorization==
| |||