English

Dynamic cycles in edge-colored multigraphs

Combinatorics 2023-03-07 v1

Abstract

Let HH be a graph possibly with loops and GG be a multigraph without loops. An HH-coloring of GG is a function c:E(G)V(H)c: E(G) \rightarrow V(H). We will say that GG is an HH-colored multigraph, whenever we are taking a fixed HH-coloring of GG. The set of all the edges with end vertices uu and vv will be denoted by EuvE_{uv}. We will say that W=(v0,e01,,e0k0,v1,e11,,e1k1,v2,,vn1,en11,,en1kn1,vn)W=(v_0,e_0^1, \ldots, e_0^{k_0},v_1,e_1^1,\ldots,e_1^{k_1},v_2,\ldots,v_{n-1},e_{n-1}^1,\ldots,e_{n-1}^{k_{n-1}},v_n), where for each ii in {0,,n1}\{0,\ldots,n-1\}, ki1k_i \geq 1 and eijEvivi+1e_i^j \in E_{v_iv_{i+1}} for every j{1,,ki}j \in \{1,\ldots, k_i \}, is a dynamic HH-walk iff c(eiki)c(ei+11)c(e_i^{k_i})c(e_{i+1}^1) is an edge in HH, for each i{0,,n2}i \in \{0,\ldots,n-2\}. We will say that a dynamic HH-walk is a closed dynamic HH-walk whenever v0=vnv_0=v_n and c(en1kn1)c(e01)c(e_{n-1}^{k_{n-1}})c(e_0^1) is an edge in HH. Moreover, a closed dynamic HH-walk is called dynamic HH-cycle whenever vivjv_i\neq v_j, for every {i,j}{0,,vn1}\{i,j\}\subseteq \{0,\ldots,v_{n-1}\}. In particular, a dynamic HH-walk is an HH-walk whenever ki=1k_i=1, for every i{0,,n1}i \in \{0,\ldots,n-1\}, and when HH is a complete graph without loops, an HH-walk is well known as a properly colored walk. In this work, we study the existence and length of dynamic HH-cycles, dynamic HH-trails and dynamic HH-paths in HH-colored multigraphs. To accomplish this, we introduce a new concept of color degree, namely, the \textit{dynamic degree}, which allows us to extend some classic results, as Ore's Theorem, for HH-colored multigraphs. Also, we give sufficient conditions for the existence of hamiltonian dynamic HH-cycles in HH-colored multigraphs, and as a consequence, we obtain sufficient conditions for the existence of properly colored hamiltonian cycle in edge-colored multigraphs, with at least c3c\geq 3 colors.

Cite

@article{arxiv.2303.02548,
  title  = {Dynamic cycles in edge-colored multigraphs},
  author = {Hortensia Galeana-Sánchez and Carlos Vilchis-Alfaro},
  journal= {arXiv preprint arXiv:2303.02548},
  year   = {2023}
}

Comments

arXiv admin note: text overlap with arXiv:2207.03623

R2 v1 2026-06-28T09:01:41.962Z