Proof of the strong 2-cover conjecture for planar graphs
The following theorem is proven without recourse to the four color theorem. Let \(G\) be a planar bridgeless graph, and let \(S_0=\{C_1,\dots,C_k\}\) be a set of edge-disjoint cycles of \(G\). Then there exists a 2-cover \(S\) of \(G\) with \(S_0\subset S\).
scientific article; zbMATH DE number 3941581