Vertex connectivity is a well-studied concept in graph theory with numerous applications. A k -connected if it remains connected after removing any −1 vertices. The vertex of the maximum such that -connected. There long history algorithmic development for efficiently computing connectivity. Recently, two near linear-time algorithms small were introduced by Forster et al. [SODA 2020]. Prior to t...

Real-world networks are prone to breakdowns. Typically in the underlying graph G, besides the insertion or deletion of edges, the set of active vertices changes overtime. A vertex might work actively, or it might fail, and gets isolated temporarily. The active vertices are grouped as a set S. S is subjected to updates, i.e., a failed vertex restarts, or an active vertex fails, and gets deleted ...

In graph theory connectivity is stated, prevailingly, in terms of paths. While exploiting a proof assistant to check formal reasoning about graphs, we chose to work with an alternative characterization of connectivity: for, within the framework of the underlying set theory, it requires virtually no preparatory notions. We say that a graphs devoid of isolated vertices is connected if no subset o...

The concept of atom-bond connectivity (ABC) index was introduced in the chemical graph theory in 1998. The atom-bond connectivity (ABC) index of a graph G defined as (see formula in text) where E(G) is the edge set and di is the degree of vertex v(i) of G. Very recently Graovac et al. define a new version of the ABC index as (see formula in text) where n(i) denotes the number of vertices of G w...

A vertex dominating path in a graph is a path P such that every vertex outside P has a neighbor on P . In 1988 H. Broersma stated a result implying that every n-vertex kconnected graph G such that σ(k+2)(G) ≥ n− 2k − 1 contains a dominating path. We show that every n-vertex k-connected graph with σ2(G) ≥ 2n k+2 + f(k) contains a dominating path of length at most O(|T |), where T is a minimum do...

An edge of a k-connected graph is said to be k-contractible if its contraction yields a k-connected graph. A non-complete k-connected graph possessing no k-contractible edges is called contraction-critical k-connected. Let G be a contraction-critical 7-connected graph with n vertices, and V7 the set of vertices of degree 7 in G. In this paper, we prove that |V7| ≥ n 22 , which improves the resu...

A graph G of order n is said to be arbitrarily vertex decomposable if for each sequence (n1, . . . , nk) of positive integers such that n1 + · · · + nk = n there exists a partition (V1, . . . , Vk) of the vertex set of G such that for each i ∈ {1, . . . , k}, Vi induces a connected subgraph of G on ni vertices. The main result of the paper reads as follows. Suppose that G is a connected graph o...

It was conjectured in [S. Akbari, F. Khaghanpoor, and S. Moazzeni. Colorful paths in vertex coloring of graphs. Preprint] that, if G is a connected graph distinct from C7, then there is a χ(G)-coloring of G in which every vertex v ∈ V (G) is an initial vertex of a path P with χ(G) vertices whose colors are different. In [S. Akbari, V. Liaghat, and A. Nikzad. Colorful paths in vertex coloring of...