Average connectivity of minimally 2-connected graphs and average edge-connectivity of minimally 2-edge-connected graphs

نویسندگان

چکیده

Let G be a (multi)graph of order n and let u,v vertices G. The maximum number internally disjoint u–v paths in is denoted by κG(u,v), the edge-disjoint λG(u,v). average connectivity defined κ¯(G)=∑κG(u,v)∕n2, edge-connectivity λ¯(G)=∑λG(u,v)∕n2, where both sums run over all unordered pairs {u,v}⊆V(G). A graph called ideally connected if κG(u,v)=min{deg(u),deg(v)} for {u,v} We prove that every minimally 2-connected with largest bipartite, set degree 2 at least 3 being partite sets. use this structure to κ¯(G)<94 any This bound asymptotically tight, we extremal obtained from some nearly regular on roughly n∕4 3n∕4 edges subdividing edge. also λ¯(G)<94 2-edge-connected G, provide similar characterization graphs.

برای دانلود باید عضویت طلایی داشته باشید

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

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Average connectivity and average edge-connectivity in graphs

Connectivity and edge-connectivity of a graph measure the difficulty of breaking the graph apart, but they are very much affected by local aspects like vertex degree. Average connectivity (and analogously, average edge-connectivity) has been introduced to give a more refined measure of the global “amount” of connectivity. In this paper, we prove a relationship between the average connectivity a...

متن کامل

Z3-connectivity of 4-edge-connected 2-triangular graphs

A graph G is k-triangular if each edge of G is in at least k triangles. It is conjectured that every 4-edge-connected 1-triangular graph admits a nowhere-zero Z3-flow. However, it has been proved that not all such graphs are Z3-connected. In this paper, we show that every 4-edge-connected 2-triangular graph is Z3-connected. The result is best possible. This result provides evidence to support t...

متن کامل

Minimally (k, k-1)-edge-connected graphs

For an interger l > 1, the l-edge-connectivity λl(G) of G is defined to be the smallest number of edges whose removal leaves a graph with at least l components, if |V (G)| ≥ l; and λl(G) = |V (G)| if |V (G)| ≤ l. A graph G is (k, l)-edge-connected if the l-edge-connectivity of G is at least k. A sufficient and necessary condition for G to be minimally (k, k − 1)-edgeconnected is obtained in the...

متن کامل

Generating connected and 2-edge connected graphs

We focus on the algorithm underlying the main result of [6]. This is an algebraic formula to generate all connected graphs in a recursive and efficient manner. The key feature is that each graph carries a scalar factor given by the inverse of the order of its group of automorphisms. In the present paper, we revise that algorithm on the level of graphs. Moreover, we extend the result subsequentl...

متن کامل

Characterization of minimally (2, l)-connected graphs

For an integer l ≥ 2, the l-connectivity κl(G) of a graph G is defined to be the minimum number of vertices of G whose removal produces a disconnected graph with at least l components or a graph with fewer than l vertices. Let k ≥ 1, a graph G is called (k, l)-connected if κl(G) ≥ k. A graph G is called minimally (k, l)-connected if κl(G) ≥ k but ∀e ∈ E(G), κl(G − e) ≤ k − 1. We present a struc...

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

ژورنال

عنوان ژورنال: Discrete Applied Mathematics

سال: 2021

ISSN: ['1872-6771', '0166-218X']

DOI: https://doi.org/10.1016/j.dam.2020.10.015