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

This conjecture is related to cycle-cover problems and is used in the paper to derive consequences for cubic-graph colorings. Its status is not resolved in the supplied text.

Equivalent formulations 1

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

  1. The (5,2)(5,2)-even-subgraph-cover conjecture

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

    This conjecture is presented as a classical consequence of the Petersen coloring conjecture. The source gives no evidence that it has been resolved.

    source: Luca Ferrarini and Vahan Mkrtchyan, “Some new results on Sylvester colorings of cubic graphs”, arXiv:2607.06396 (2026).

Sources & referencesView supporting material

Primary source

Anush Hakobyan and Vahan Mkrtchyan, “S_12 and P_12-colorings of cubic graphs”, arXiv:1807.08138 (2018).

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