Non-separating trees in connected graphs

Non-separating trees in connected graphs

Let T be any tree of order d ≥ 1. We prove that every connected graph G with minimum degree d contains a subtree T ′ isomorphic to T such that G − V (T ) is connected.

Independent Trees in 4-Connected Graphs

Non-separating Induced Cycles in Graphs

In this paper we consider non-separating induced cycles in graphs. A basic result is that any 2-connected graph with at least six vertices and without such a cycle has at least four vertices of degree 2, and this is best possible. For any 3-connected graph G we prove that there exists a non-separating induced cycle C, such that all cycles in G V(C) are contained in the same block of G V(C). We ...

Spanning k-Trees of n-Connected Graphs

A tree is called a k-tree if the maximum degree is at most k. We prove the following theorem, by which a closure concept for spanning k-trees of n-connected graphs can be defined. Let k ≥ 2 and n ≥ 1 be integers, and let u and v be a pair of nonadjacent vertices of an n-connected graph G such that degG(u)+degG(v) ≥ |G|−1−(k−2)n, where |G| denotes the order of G. Then G has a spanning k-tree if ...

Locally connected spanning trees on graphs

A locally connected spanning tree of a graph G is a spanning tree T of G such that the set of all neighbors of v in T induces a connected subgraph of G for every v ∈ V (G). The purpose of this paper is to give linear-time algorithms for finding locally connected spanning trees on strongly chordal graphs and proper circular-arc graphs, respectively.