Contractible Edges in 2-Connected Locally Finite Graphs
نویسنده
چکیده
In this paper, we prove that every contraction-critical 2-connected infinite graph has no vertex of finite degree and contains uncountably many ends. Then, by investigating the distribution of contractible edges in a 2-connected locally finite infinite graph G, we show that the closure of the subgraph induced by all the contractible edges in the Freudenthal compactification of G is 2-arc-connected. Finally, we characterize all 2-connected locally finite outerplanar graphs nonisomorphic to K3 as precisely those graphs such that every vertex is incident to exactly two contractible edges as well as those graphs such that every finite bond contains exactly two contractible edges.
منابع مشابه
Hamiltonicity in Locally Finite Graphs: Two Extensions and a Counterexample
We state a sufficient condition for the square of a locally finite graph to contain a Hamilton circle, extending a result of Harary and Schwenk about finite graphs. We also give an alternative proof of an extension to locally finite graphs of the result of Chartrand and Harary that a finite graph not containing K4 or K2,3 as a minor is Hamiltonian if and only if it is 2-connected. We show furth...
متن کاملContractible edges in 3-connected graphs
By a graph, we mean a finite undirected simple graph with no loops and no multiple edges. For a graph G and an edge e of G, we let G/e denote the graph obtained from G by contracting e (and replacing each pair of the resulting double edges by a simple edge). Let k ≥ 2 be an integer, and let G be a k-connected graph. An edge e of G is said to be k-contractible if G/e is k-connected. The set of k...
متن کاملOn the number of 4-contractible edges in 4-connected graphs
We prove that every finite 4-connected graph G has at least 1 34 · (|E(G)| − 2|V (G)|) many contractible edges. AMS subject classification: 05c40, 05c35.
متن کاملMore on foxes
An edge in a k-connected graph G is called k-contractible if the graph G/e obtained from G by contracting e is k-connected. Generalizing earlier results on 3-contractible edges in spanning trees of 3-connected graphs, we prove that (except for the graphs Kk+1 if k ∈ {1, 2}) (a) every spanning tree of a k-connected triangle free graph has two k-contractible edges, (b) every spanning tree of a k-...
متن کاملThe 3-connected graphs with a longest path containing precisely two contractible edges
Previously the authors characterized the 3-connected graphs with a Hamilton path containing only two contractible edges. In this paper we extend this result by showing that if a 3-connected graph has a diameter containing only two contractible edges, then that diameter is a Hamilton path. INTRODUCTION AND TERMINOLOGY All graphs in this paper are finite, undirected and simple. Let G be a 3-conne...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Electr. J. Comb.
دوره 22 شماره
صفحات -
تاریخ انتشار 2015