Linear forest

In graph theory, a branch of mathematics, a linear forest is a kind of forest where each component is a path graph,:200 or a disjoint union of nontrivial paths.:246 Equivalently, it is an acyclic and claw-free graph.:130,131 An acyclic graph where every vertex has degree 0, 1, or 2 is a linear forest.:310:107 An undirected graph has Colin de Verdière graph invariant at most 1 if and only if it is a (node-)disjoint union of paths, i.e. it is linear.:13,19–21:29,35,67 (3,6,29) Any linear forest is a subgraph of the path graph with the same number of vertices.:55