Homeomorphically irreducible spanning trees

نویسندگان

  • Guantao Chen
  • Songling Shan
چکیده

We show that if G is a graph such that every edge is in at least two triangles, then G contains a spanning tree with no vertex of degree 2 (a homeomorphically irreducible spanning tree). This result was originally asked in a question format by Albertson, Berman, Hutchinson, and Thomassen in 1979, and then conjectured to be true by Archdeacon in 2009. MSC2010 : 05C05, 05C75

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Homeomorphically Irreducible Spanning Trees, Halin Graphs, and Long Cycles in 3-connected Graphs with Bounded Maximum Degrees

A tree T with no vertex of degree 2 is called a homeomorphically irreducible tree (HIT) and if T is spanning in a graph, then T is called a homeomorphically irreducible spanning tree (HIST). Albertson, Berman, Hutchinson and Thomassen asked if every triangulation of at least 4 vertices has a HIST and if every connected graph with each edge in at least two triangles contains a HIST. These two qu...

متن کامل

Homeomorphically Irreducible Spanning Trees in Locally Connected Graphs

A spanning tree T of a graph G is called a homeomorphically irreducible spanning tree (HIST) if T does not contain vertices of degree 2. A graph G is called locally connected if for every vertex v ∈ V (G), the subgraph induced by the neighborhood of v is connected. In this paper, we prove that every connected and locally connected graph with more than 3 vertices contains a HIST. Consequently, w...

متن کامل

Counting Trees

Let t n denote the number of unlabeled trees on n vertices. Let t(x) = P 1 n=1 t n x n be the corresponding generating function. Similarly, let T n , h n , and i n denote the numbers of rooted trees, homeomorphically irreducible trees, and identity trees on n vertices, respectively. (Homeomorphically irre-ducible trees have no vertices of degree 2, and identity trees have trivial au-tomorphism ...

متن کامل

A characterization of P5-free graphs with a homeomorphically irreducible spanning tree

A spanning tree with no vertices of degree two is called a homeomorphically irreducible spanning tree (or a HIST ) of a graph. In [7], sets of forbidden subgraphs that imply the existence of a HIST in a connected graph of sufficiently large order were characterized. In this paper, we focus on characterizing connected P5-free graphs which have a HIST. As applications of our main result, we also ...

متن کامل

Spanning tree congestion critical graphs

The linear or cyclic cutwidth of a graph G is the minimum congestion when G is embedded into either a path or a cycle respectively. A graph is cutwith critical if it is homeomorphically minimal and all of its subgraphs have lower cutwitdth. Our purpose is to extend the study of congestion critical graphs to embeddings on spanning trees.

متن کامل

ذخیره 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 نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • J. Comb. Theory, Ser. B

دوره 103  شماره 

صفحات  -

تاریخ انتشار 2013