The (5, 2)-cycle-cover conjecture

Let GG be a bridgeless graph, not necessarily cubic. An even subgraph is a subgraph in which every vertex has even degree.

The (5, 2)-cycle-cover conjecture. The graph GG contains five even subgraphs such that every edge of GG belongs to exactly two of them.

This is a cycle-cover conjecture extending the perfect-matching formulation beyond cubic graphs. The source attributes it to Seymour and Szekeres, and its resolution is not supplied in the source.

Equivalent formulations 2

Other statements of this same problem, merged from separate entries. Each is equivalent to the statement above — proving any one settles them all.

  1. (5,2)(5,2)-cycle-cover conjecture

    Let GG be a bridgeless graph, not necessarily cubic. An even subgraph is a subgraph in which every vertex of GG has even degree. (5,2)(5,2)-cycle-cover conjecture. The graph GG contains five even subgraphs such that every edge belongs to exactly two of them. The conjecture is presented as a classical consequence implied by the Petersen coloring conjecture.

    source: Vahan V. Mkrtchyan, “A remark on Petersen coloring conjecture of Jaeger”, arXiv:1201.4472 (2012).

  2. The (5,2)(5,2)-cycle-cover conjecture

    Let GG be a bridgeless graph, not necessarily cubic. An even subgraph is a subgraph in which every vertex has even degree. The (5,2)(5,2)-cycle-cover conjecture. The graph GG contains five even subgraphs such that every edge of GG belongs to exactly two of them. This is one of the classical cycle-cover conjectures related to Petersen coloring and remains open.

    source: Vahan Mkrtchyan, “Non-conflicting no-where zero Z_2Z_2 flows in cubic graphs”, arXiv:2410.04389 (2024).

Sources & referencesView supporting material

Primary source

Anush Hakobyan and Vahan Mkrtchyan, “On Sylvester Colorings of Cubic Graphs”, arXiv:1511.02475 (2018).

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