“…Moreover, equality holds in (2) if u and v are in different branches when ω = 1 and in opposite branches when ω ≥ 2.…”
Section: A Lower Bound For Hamiltonian Chromatic Number Of Block Graphsmentioning
confidence: 99%
“…Thus the hamiltonian chromatic number of a connected graph G measures how close G is to being hamiltonian-connected, minimum the hamiltonian chromatic number of a connected graph G is, the closer G is to being hamiltonian-connected. The concept of hamiltonian coloring was introduced by Chartrand et al [2] as a variation of radio k-coloring of graphs.…”
Section: Introductionmentioning
confidence: 99%
“…Without loss of generality, we initiate with label 0, then the span of any hamiltonian coloring c which is defined as max{|c(u) − c(v)| : u, v ∈ V (G)}, is the maximum integer used for coloring. However, in [2,3,6] only positive integers are used as colors. Therefore, the hamiltonian chromatic number defined in this article is one less than that defined in [2,3,6] and hence we will make necessary adjustment when we present the results of [2,3,6] in this article.…”
Abstract. A hamiltonian coloring c of a graph G of order p is an assignment of colors to the vertices of G such that D(u, v) + |c(u)−c(v)| ≥ p − 1 for every two distinct vertices u and v of G, where D(u, v) denotes the detour distance between u and v. The value hc(c) of a hamiltonian coloring c is the maximum color assigned to a vertex of G. The hamiltonian chromatic number, denoted by hc(G), is the min{hc(c)} taken over all hamiltonian coloring c of G. In this paper, we present a lower bound for the hamiltonian chromatic number of block graphs and give a sufficient condition to achieve the lower bound. We characterize symmetric block graphs achieving this lower bound. We present two algorithms for optimal hamiltonian coloring of symmetric block graphs.
“…Moreover, equality holds in (2) if u and v are in different branches when ω = 1 and in opposite branches when ω ≥ 2.…”
Section: A Lower Bound For Hamiltonian Chromatic Number Of Block Graphsmentioning
confidence: 99%
“…Thus the hamiltonian chromatic number of a connected graph G measures how close G is to being hamiltonian-connected, minimum the hamiltonian chromatic number of a connected graph G is, the closer G is to being hamiltonian-connected. The concept of hamiltonian coloring was introduced by Chartrand et al [2] as a variation of radio k-coloring of graphs.…”
Section: Introductionmentioning
confidence: 99%
“…Without loss of generality, we initiate with label 0, then the span of any hamiltonian coloring c which is defined as max{|c(u) − c(v)| : u, v ∈ V (G)}, is the maximum integer used for coloring. However, in [2,3,6] only positive integers are used as colors. Therefore, the hamiltonian chromatic number defined in this article is one less than that defined in [2,3,6] and hence we will make necessary adjustment when we present the results of [2,3,6] in this article.…”
Abstract. A hamiltonian coloring c of a graph G of order p is an assignment of colors to the vertices of G such that D(u, v) + |c(u)−c(v)| ≥ p − 1 for every two distinct vertices u and v of G, where D(u, v) denotes the detour distance between u and v. The value hc(c) of a hamiltonian coloring c is the maximum color assigned to a vertex of G. The hamiltonian chromatic number, denoted by hc(G), is the min{hc(c)} taken over all hamiltonian coloring c of G. In this paper, we present a lower bound for the hamiltonian chromatic number of block graphs and give a sufficient condition to achieve the lower bound. We characterize symmetric block graphs achieving this lower bound. We present two algorithms for optimal hamiltonian coloring of symmetric block graphs.
“…Chartrand et al [7] observed that in case of paths P n , d = n − 1 and d(u, v) is same as the the length of a longest u − v path which is denoted by D(u, v) known as detour distance between u and v, then (1) is equivalent to D(u, v) + |c(u) − c(v)| ≥ n − 1.…”
Section: Introductionmentioning
confidence: 99%
“…Note that any optimal hamiltonian coloring always assign label 0 to some vertex, then the span of any hamiltonian coloring c which is defined as max{|c(u)− c(v)| : u, v ∈ V (G)}, is the maximum integer used for coloring. However, in [7,8,10] only positive integers are used as colors. Therefore, the hamiltonian chromatic number defined in this article is one less than that defined in [7,8,10].…”
Let G be a simple connected graph of order n. A hamiltonian coloring c of a graph G is an assignment of colors (non-negative integers) to the vertices of G such that D(u, v) + |c(u) − c(v)| ≥ n − 1 for every two distinct vertices u and v of G, where D(u, v) denotes the detour distance between u and v in G which is the length of the longest path between u and v. The value hc(c) of a hamiltonian coloring c is the maximum color assigned to a vertex of G. The hamiltonian chromatic number, denoted by hc(G), is min{hc(c)} taken over all hamiltonian coloring c of G. In this paper, we give a necessary and sufficient condition to achieve a lower bound for the hamiltonian chromatic number of block graphs given in [1, Theorem 1]. We present an algorithm for optimal hamiltonian coloring of a special class of block graphs, namely SDB(p/2) block graphs. We characterize level-wise regular block graphs and extended star of blocks achieving this lower bound.
A hamiltonian coloring c of a graph G of order n is a mapping c : V (G) → {0, 1, 2, ...} such that D(u, v) + |c(u) − c(v)| ≥ n − 1, for every two distinct vertices u and v of G, where D(u, v) denotes the detour distance between u and v which is the length of a longest u, v-path in G. The value hc(c) of a hamiltonian coloring c is the maximum color assigned to a vertex of G. The hamiltonian chromatic number, denoted by hc(G), is the min{hc(c)} taken over all hamiltonian coloring c of G. In this paper, we present a lower bound for the hamiltonian chromatic number of trees and give a sufficient condition to achieve this lower bound. Using this condition we determine the hamiltonian chromatic number of symmetric trees, firecracker trees and a special class of caterpillars.
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