
Utilitas Mathematica
ISSN: 0315-3681 (print)
Utilitas Mathematica is a historical journal that focuses on sharing research in statistical designs and combinatorial mathematics. It has been publishing since 1972. From 2024 onward, it publishes four volumes per year in March, June, September and December. Utilitas Mathematica has gained recognition and visibility in the academic community and is indexed in renowned databases such as MathSciNet, Zentralblatt, and Scopus. The scope of the journal includes; graph theory, design theory, extremal combinatorics, enumeration, algebraic combinatorics, combinatorial optimization, discrete geometry, convex geometry, Ramsey theory, automorphism groups, coding theory, finite geometries, chemical graph theory, etc.
- Research article
- https://doi.org/10.61091/um121-07
- Full Text
- Utilitas Mathematica
- Volume 121
- Pages: 91-103
- Published: 31/12/2024
Total dominator total coloring of a graph is a total coloring of the graph such that each object of the graph is adjacent or incident to every object of some color class. The minimum namber of the color classes of a total dominator total coloring of a graph is called the total dominator total chromatic number of the graph. Here, we will find the total dominator chromatic numbers of wheels, complete bipartite graphs and complete graphs.
- Research article
- https://doi.org/10.61091/um121-06
- Full Text
- Utilitas Mathematica
- Volume 121
- Pages: 69-90
- Published: 31/12/2024
We initiate to study a
- Research article
- https://doi.org/10.61091/um121-05
- Full Text
- Utilitas Mathematica
- Volume 121
- Pages: 53-68
- Published: 31/12/2024
A proper coloring assigns distinct colors to the adjacent vertices of a graph. An equitable near proper coloring of a graph
- Research article
- https://doi.org/10.61091/um121-04
- Full Text
- Utilitas Mathematica
- Volume 121
- Pages: 37-52
- Published: 31/12/2024
Directed hypergraphs represent a natural extension of directed graphs, while soft set theory provides a method for addressing vagueness and uncertainty. This paper introduces the notion of soft directed hypergraphs by integrating soft set principles into directed hypergraphs. Through parameterization, soft directed hypergraphs yield a sequence of relation descriptions derived from a directed hypergraph. Additionally, we present several operations for soft directed hypergraphs, including extended union, restricted union, extended intersection, and restricted intersection, and explore their characteristics.
- Research article
- https://doi.org/10.61091/um121-03
- Full Text
- Utilitas Mathematica
- Volume 121
- Pages: 25-35
- Published: 31/12/2024
For a connected graph
- Research article
- https://doi.org/10.61091/um121-02
- Full Text
- Utilitas Mathematica
- Volume 121
- Pages: 11-24
- Published: 31/12/2024
Given a connected graph
- Research article
- https://doi.org/10.61091/um121-01
- Full Text
- Utilitas Mathematica
- Volume 121
- Pages: 3-9
- Published: 31/12/2024
By means of the generating function method, a linear recurrence relation is explicitly resolved. The solution is expressed in terms of the Stirling numbers of both the first and the second kind. Two remarkable pairs of combinatorial identities (Theorems 3.1 and 3.3) are established as applications, that contain some well–known convolution formulae on Stirling numbers as special cases.
- Research article
- https://doi.org/10.61091/um120-08
- Full Text
- Utilitas Mathematica
- Volume 120
- Pages: 93-107
- Published: 30/09/2024
For a graph G and for non-negative integers p, q, and r, the triplet
- Research article
- https://doi.org/10.61091/um120-07
- Full Text
- Utilitas Mathematica
- Volume 120
- Pages: 75-91
- Published: 30/09/2024
A graph G(V, E) is Γ-harmonious when there is an injection f from V to an Abelian group Γ such that the induced edge labels defined as w(xy) = f(x) + f(y) form a bijection from E to Γ. We study Γ-harmonious labelings of several cycles-related classes of graphs, including Dutch windmills, generalized prisms, generalized closed and open webs, and superwheels.
- Research article
- https://doi.org/10.61091/um120-06
- Full Text
- Utilitas Mathematica
- Volume 120
- Pages: 61-74
- Published: 30/09/2024
If Γ is a finite group and G a graph such that Aut(G) ≡ Γ acts regularly on V(G), then we say that G is a graphical regular representation (GRR) of Γ. The question asking which finite groups have at least one GRR was an important question in algebraic graph theory and it was completely solved as a result of work done by several researchers. However, it remains a challenge to discern whether a group known to have GRRs has GRRs with specific properties, such as being trivalent. In this paper, we shall be deriving simple conditions on the parameters of a subset of a dihedral group for easily constructing trivalent graphical regular representations (GRR) of the group. Specifically, we shall prove the following:
Let n be an odd integer greater than 5 and let r, s, and t be integers less than n such that the difference of any two of them is relatively prime to n. If 3r – 2s = t (mod n), then Cay(Dn, {abr, abs, abt}) is a GRR of Dn.
We will also be looking at very convenient corollaries of this result. But another main aim of this paper is to show how a simple use of Schur rings can be used to derive such results. This paper therefore also serves as a review of some basic results about Schur rings which we feel should be among the standard armory of an algebraic graph theorist.
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