HAMILTONICITY OF CAMOUFLAGE GRAPHS

This paper examines the Hamiltonicity of graphs having some hidden behaviours of some other graphs in it. The well-known mathematician Barnette introduced the open conjecture which becomes a theorem by restricting our attention to the class of graphs which is 3-regular, 3- connected, bipartite, planar graphs having odd number of vertices in its partition be proved as a Hamiltonian. Consequently the result proved in this paper stated that “Every connected vertex-transitive simple graph has a Hamilton path” shows a significant improvement over the previous efforts by L.Babai and L.Lovasz who put forth this conjecture. And we characterize a graphic sequence which is forcibly Hamiltonian if every simple graph with degree sequence is Hamiltonian. Thus we discussed about the concealed graphs which are proven to be Hamiltonian.

LogoJS: a Javascript package for creating sequence logos and embedding them in web applications

Summary Sequence logos were introduced nearly 30 years ago as a human-readable format for representing consensus sequences, and they remain widely used. As new experimental and computational techniques have developed, logos have been extended: extra symbols represent covalent modifications to nucleotides, logos with multiple letters at each position illustrate models with multi-nucleotide features and symbols extending below the x-axis may represent a binding energy penalty for a residue or a negative weight output from a neural network. Web-based visualization tools for genomic data are increasingly taking advantage of modern web technology to offer dynamic, interactive figures to users, but support for sequence logos remains limited. Here, we present LogoJS, a Javascript package for rendering customizable, interactive, vector-graphic sequence logos and embedding them in web applications. LogoJS supports all the aforementioned logo extensions and is bundled with a companion web application for creating and sharing logos. Availability and implementation LogoJS is implemented both in plain Javascript and ReactJS, a popular user-interface framework. The web application is hosted at logojs.wenglab.org. All major browsers and operating systems are supported. The package and application are open-source; code is available at GitHub. Contact [email protected] Supplementary information Supplementary data are available at Bioinformatics online.

A note on the potential function of an arbitrary graph H

Given a graph H, a graphic sequence ? is potentially H-graphic if there is a realization of ? containing H as a subgraph. In 1991, Erd?s et al. introduced the following problem: determine the minimum even integer ?(H,n) such that each n-term graphic sequence with sum at least ?(H,n) is potentially H-graphic. This problem can be viewed as a ?potential? degree sequence relaxation of the Tur?n problems. Let H be an arbitrary graph of order k. Ferrara et al. [Combinatorica, 36(2016)687-702] established an upper bound on ?(H,n): if ? = ?(n) is an increasing function that tends to infinity with n, then there exists an N = N(?,H) such that ?(H,n)? ?~(H)n + ?(n) for any n ? N, where ?~(H) is a parameter only depending on the graph H. Recently, Yin [European J. Combin., 85(2020)103061] obtained a new upper bound on ?(H,n): there exists an M = M(k,?(H)) such that ?(H,n) ? ?~(H)n + k2-3k+4 for any n ? M. In this paper, we investigate the precise behavior of ?(H,n) for arbitrary H with ?~?(H)+1(H < ?~(H) or??(H)+1(H) ? 2, where ??(H)+1(H) = min{?F)|F is an induced subgraph of H and |V(F)|= ?(H) + 1} and ?~?(H)+1(H) = 2(k-?(H)-1)+??(H)+1(H)-1. Moreover, we also show that ?(H,n) = (k-?(H)-1)(2n-k+?(H))+2 for those H so that ??(H)+1(H) = 1,?~?(H)+1(H)=~?~(H),?~p(H) < ?~(H) for ?(H) + 2 ? p ? k and there is an F < H with |V(F)| = ?(H) + 1 and ?(F) = (12,0?(H)-1).

A further result on the potential-Ramsey number of G1 and G2

A non-increasing sequence ? = (d1,. . ., dn) of nonnegative integers is a graphic sequence if it is realizable by a simple graph G on n vertices. In this case, G is referred to as a realization of ?. Given a graph H, a graphic sequence ? is potentially H-graphic if ? has a realization containing H as a subgraph. Busch et al. (Graphs Combin., 30(2014)847-859) considered a degree sequence analogue to classical graph Ramsey number as follows: for graphs G1 and G2, the potential-Ramsey number rpot(G1,G2) is the smallest non-negative integer k such that for any k-term graphic sequence ?, either ? is potentially G1-graphic or the complementary sequence ? = (k - 1 - dk,..., k - 1 - d1) is potentially G2-graphic. They also gave a lower bound on rpot(G;Kr+1) for a number of choices of G and determined the exact values for rpot(Kn;Kr+1), rpot(Cn;Kr+1) and rpot(Pn,Kr+1). In this paper, we will extend the complete graph Kr+1 to the complete split graph Sr,s = Kr ? Ks. Clearly, Sr,1 = Kr+1. We first give a lower bound on rpot(G, Sr,s) for a number of choices of G, and then determine the exact values for rpot(Cn, Sr,s) and rpot(Pn, Sr,s).

On multigraphic and potentially multigraphic sequences

An r-graph(or a multigraph) is a loopless graph in which no two vertices are joined by more than r edges. An r-complete graph on n vertices, denoted by Kn(r), is an r-graph on n vertices in which each pair of vertices is joined by exactly r edges. A non-increasing sequence π = (d1,d2,..., dn) of non-negative integers is said to be r-graphic if it is realizable by an r-graph on n vertices. An r-graphic sequence π is said to be potentially SL;M(r)-graphic if it has a realization containing SL;M(r)as a subgraph. We obtain conditions for an r-graphic sequence to be potentially S(r) L;M-graphic. These are generalizations from split graphs to p-tuple r-split graph.

An extremal problem for a graphic sequence to have a realization containing every 2-tree with prescribed size

International audience A graph $G$ is a $2$<i>-tree</i> if $G=K_3$, or $G$ has a vertex $v$ of degree 2, whose neighbors are adjacent, and $G-v$ is a 2-tree. Clearly, if $G$ is a 2-tree on $n$ vertices, then $|E(G)|=2n-3$. A non-increasing sequence $\pi =(d_1, \ldots ,d_n)$ of nonnegative integers is a <i>graphic sequence</i> if it is realizable by a simple graph $G$ on $n$ vertices. Yin and Li (Acta Mathematica Sinica, English Series, 25(2009)795&#x2013;802) proved that if $k \geq 2$, $n \geq \frac{9}{2}k^2 + \frac{19}{2}k$ and $\pi =(d_1, \ldots ,d_n)$ is a graphic sequence with $\sum \limits_{i=1}^n d_i > (k-2)n$, then $\pi$ has a realization containing every tree on $k$ vertices as a subgraph. Moreover, the lower bound $(k-2)n$ is the best possible. This is a variation of a conjecture due to Erd&#x0151;s and S&oacute;s. In this paper, we investigate an analogue extremal problem for 2-trees and prove that if $k \geq 3$, $n \geq 2k^2-k$ and $\pi =(d_1, \ldots ,d_n)$ is a graphic sequence with $\sum \limits_{i=1}^n d_i > \frac{4kn}{3} - \frac{5n}{3}$ then $\pi$ has a realization containing every 2-tree on $k$ vertices as a subgraph. We also show that the lower bound $\frac{4kn}{3} - \frac{5n}{3}$ is almost the best possible.

Torre de los Escipiones: de la interpretación a la divulgación del patrimonio

The Torre de los Escipiones is a tower shape monument 6 km away from the city of Tarragona. Although it is incomplete, its good state of preservation makes it an iconic landmark of the area. It is an isolated construction in the landscape, which favours a certain misunderstanding. We believe it is necessary to develop a strategy to help its dissemination. In this case, the disclosure not only understood as the reconstruction of an hypothetical appearance in Roman times but also to imply the symbolic and social dimensions of Roman funerary world and how this is reflicted in its architecture. On the other hand, the Torre de los Escipiones has also been used as a study to test the ability of scientific research to connect with the disclosure to the public. That is, to develop from the working group itself the graphic sequence in which the work is shown: from the documentation of the remains to the analysis, interpretation and proposed restitution. Thus, not only the disclosure of the monument itself is achieved, but also demostrates how science contributes to the cultural enrichment of society.

On the simultaneous edge coloring of graphs

A μ-simultaneous edge coloring of graph G is a set of μ proper edge colorings of G with a same color set such that for each vertex, the sets of colors appearing on the edges incident to that vertex are the same in each coloring and no edge receives the same color in any two colorings. The μ-simultaneous edge coloring of bipartite graphs has a close relation with μ-way Latin trades. Mahdian et al. (2000) conjectured that every bridgeless bipartite graph is 2-simultaneous edge colorable. Luo et al. (2004) showed that every bipartite graphic sequence S with all its elements greater than one, has a realization that admits a 2-simultaneous edge coloring. In this paper, the μ-simultaneous edge coloring of graphs is studied. Moreover, the properties of the extremal counterexample to the above conjecture are investigated. Also, a relation between 2-simultaneous edge coloring of a graph and a cycle double cover with certain properties is shown and using this relation, some results about 2-simultaneous edge colorable graphs are obtained.