Utilitas Algorithmica (UA)
ISSN: xxxx-xxxx (print)
Utilitas Algorithmica (UA) is a premier, open-access international journal dedicated to advancing algorithmic research and its applications. Launched to drive innovation in computer science, UA publishes high-impact theoretical and experimental papers addressing real-world computational challenges. The journal underscores the vital role of efficient algorithm design in navigating the growing complexity of modern applications. Spanning domains such as parallel computing, computational geometry, artificial intelligence, and data structures, UA is a leading venue for groundbreaking algorithmic studies.
- Research article
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 039
- Pages: 107-120
- Published: 30/11/2001
Let \(G\) be a bipartite graph with bipartite sets \(V_1\) and \(V_2\). If \(f\) is a bijective function from the vertices and edges of \(G\) into the first \(p+q\) positive integers, where \(p\) and \(q\) denote the order and size of \(G\), respectively, meeting the properties that \(f\) is a super edge magic labeling and if the cardinal of \(V_i\) is \(p_i\) for \(i=1,2\), then the image of the set \(V_1\) is the set of the first \(p_i\) positive integers and the image of the set \(V_2\) is the set of integers from \(p_1 + 1\) up to \(p\). If a bipartite graph \(G\) admits an special super edge magic labeling, we say that \(G\) is special super edge magic. Some properties of special super edge magic graphs are presented. However, this work is mainly devoted to the study of the relations existing between super edge magic and special super edge magic labelings.
- Research article
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 039
- Pages: 93-106
- Published: 30/11/2001
In this note, we present necessary conditions for decomposing \(\lambda K_n\) into copies of \(K_{2,5}\), and show that these conditions are sufficient except for \(\lambda = 5\) and \(n = 8\), and possibly for the following cases: \(\lambda = 1\) and \(n = 40\); and \(\lambda = 3\) and \(n = 16\) or \(20\).
- Research article
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 039
- Pages: 79-91
- Published: 30/11/2001
We obtain \(135\) nonisomorphic nearly Kirkman triple systems of order \(18\) (the smallest order for which such a system exists), including all \(119\) systems of a well-defined subclass.
- Research article
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 039
- Pages: 65-78
- Published: 30/11/2001
In overloaded task systems, it is by definition not possible to complete all tasks by their deadlines. However, it may still be desirable to maximize the number of in-time task completions. The performance of on-line schedulers with respect to this metric is investigated here. It is shown that in general, an on-line algorithm may perform arbitrarily poorly as compared to clairvoyant (off-line) schedulers. This result holds for general task workloads where there are no constraints on task characteristics. For a variety of constrained workloads that are representative of many practical applications, however, on-line schedulers that do provide a guaranteed level of performance are presented.
- Research article
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 039
- Pages: 49-63
- Published: 30/11/2001
We present a new algorithm for computer searches for orthogonal designs. Then we use this algorithm to find new sets of sequences with entries from \(\{0,\pm a, \pm b, \pm c,\pm d\}\) on the commuting variables \(a, b, c, d\) with zero autocorrelation function.
- Research article
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 039
- Pages: 33-48
- Published: 30/11/2001
Consider the hit polynomial of the path \(P_{2n}\) embedded in the complete graph \(K_{2n}\). We give a combinatorial interpretation of the \(n\)-th Bessel polynomial in terms of a modification of this hit polynomial, called the ordered hit polynomial. Also, the first derivative of the \(n\)-th Bessel polynomial is shown to be the ordered hit polynomial of \(P_{2n-1}\) embedded in \(K_{2n}\).
- Research article
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 039
- Pages: 19-32
- Published: 30/11/2001
In a packer-spoiler game on a graph, two players jointly construct a maximal partial \(F\)-packing of the graph according to some rules, where \(F\) is some given graph. The packer wins if all the edges are used up and the spoiler wins otherwise. The question of which graphs are wins for which player generalizes the questions of which graphs are \(F\)-packable and which are randomly \(F\)-packable. While in general such games are NP-hard to solve, we provide partial results for \(F = P_3\) and solutions for \(F = 2K_2\).
- Research article
- Full Text
- Journal of Combinatorial Mathematics and Combinatorial Computing
- Volume 039
- Pages: 3-17
- Published: 30/11/2001
Let G be a \((p,q)\)-graph with p vertices and q edges. An edge-labeling assignment \(\text{L : E} \to \text{N}\) is a map which assigns a positive integer to each edge in E. The induced map \(\text{L}^+ : \text{V} \to \text{N}\) defined by \(\text{L}^+\text{(v)} = \Sigma\{\text{L(u,v) : for all (u,v) in E}\}\) is called the vertex sum. The edge labeling assignment is called \underline{magic} if \(\text{L}^+\) is a constant map. If L is a bijection with \(\text{L(E)} = \{1,2,\ldots,\text{q}\}\) and L is magic then we say L is supermagic. B. M. Stewart showed that \(\text{K}_5\) is not supermagic and when \(\text{n} \equiv 0 \pmod{4}\) , \(\text{K}_\text{n}\) is not supermagic. In this paper, we exhibit supermagicness for a class of regular complete k-partite graphs.
- Research article
- Full Text
- Ars Combinatoria
- Volume 061
- Pages: 313-318
- Published: 31/10/2001
We give necessary and sufficient conditions for the existence of a decomposition of the complete graph into stars which admits either a cyclic or a rotational automorphism.
- Research article
- Full Text
- Ars Combinatoria
- Volume 061
- Pages: 301-312
- Published: 31/10/2001
This paper deals with combinatorial aspects of designs for two-way elimination of heterogeneity for making all possible paired comparisons of treatments belonging to two disjoint sets of treatments. Balanced bipartite row-column (BBPRC) designs have been defined which estimate all the elementary contrasts involving two treatments one from each of the two disjoint sets with the same variance. General efficiency balanced row-column designs (GEBRC) are also defined. Some general methods of construction of BBPRC designs have been given using the techniques of reinforcement, deletion (addition) of column or row structures, merging of treatments, balanced bipartite block (BBPB) designs, juxtaposition, etc. Some methods of construction give GEBRC designs also.




