On Barnette's Conjecture and $H^{+-}$ property

Abstract

A conjecture of Barnette states that every 3-connected cubic bipartite plane graph has a Hamilton cycle, which is equivalent to the statement that every simple even plane triangulation admits a partition of its vertex set into two subsets so that each induces a tree. Let $G$ be a simple even plane triangulation and suppose that ${V_1, V_2, V_3}$ is a 3-coloring of the vertex set of $G$. Let $B_{i}$, $i = 1, 2, 3$, be the set of all vertices in $V_i$ of the degree at least 6. We prove that if induced graphs $G[B_1 \cup B_2]$ and $G[B_1 \cup B_3]$ are acyclic, then the following properties are satisfied: [6pt] (1) For every path $abc$ there is possible to partition the vertex set of $G$ into two subsets so that each induces a tree, and one of them contains the edge $ab$ and avoids the vertex $c$, [6pt] (2) For every path $abc$ with vertices $a$, $c$ of the same color there is possible to partition the vertex set of $G$ into two subsets so that each induces a tree, and one of them contains the path $abc$.