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# A Characterization of T 1 Spaces via Limit Sets of Nets

Mathematica Pannonica
Author:
Yu-Lin Chou

This article indicates another set-theoretic formula, solely in terms of union and intersection, for the set of the limits of any given sequence (net, in general) in an arbitrary T 1 space; this representation in particular gives a new characterization of a T 1 space.

Open access

# Completely Multiplicative Functions with Special Properties

Mathematica Pannonica
Authors:
Imre Kátai
and
Bui M. Phong

We give all solutions of completely multiplicative functions ƒ , g, for which the equation Ag(n + 1) = Bƒ (n) + C holds for every n ∈ ℕ. We also study the equation G(p + 1) = F(p − 1) + D and we prove some results concerning it.

Open access

# Batch Scheduling with Time Restriction and Clique Search

Mathematica Pannonica
Author:
Sándor Szabó

We consider a graph whose vertices are legally colored using k colors and ask if the graph contains a k-clique. As it turns out this very special type of k-clique problem is in an intimate connection with constructing schedules. The practicality this clique search based construction of schedules is checked by carrying out numerical experiments.

Open access

# Determinant Inequalities for Positive Definite Matrices via Cartwright–Field’s Result for Arithmetic and Geometric Weighted Means

Mathematica Pannonica
Author:
Silvestru Sever Dragomir

Assume that Aj, j ∈ {1, … , m} are positive definite matrices of order n. In this paper we prove among others that, if 0 < l InAj, j ∈ {1, … , m} in the operator order, for some positive constant l, and In is the unity matrix of order n, then

$o≤12∑k=1mPk1−Pkdet2Aj−lIn−1/2−2∑1≤j

where Pk ≥ 0 for k ϵ {1, …, m} and $∑j=1mPj=1$.

Open access

# Evolutes of Conics in the Pseudo-Euclidean Plane

Mathematica Pannonica
Author:
Ivana Božić Dragun

The evolute of a conic in the pseudo-Euclidean plane is the locus of centers of all its osculating circles. It’s a curve of order six and class four in general case. In this paper we discuss and compute the order and class of evolutes of different types of conics. We will highlight those cases that have no analogy in the Euclidean plane.

Open access

# On Quasi I-Statistical Convergence of Triple Sequences in Cone Metric Spaces

Mathematica Pannonica
Authors:
Işıl Açık Demırcı
,
Ömer Kışı
, and
Mehmet Gürdal

Fast [12] is credited with pioneering the field of statistical convergence. This topic has been researched in many spaces such as topological spaces, cone metric spaces, and so on (see, for example [19, 21]). A cone metric space was proposed by Huang and Zhang [17]. The primary distinction between a cone metric and a metric is that a cone metric is valued in an ordered Banach space. Li et al. [21] investigated the definitions of statistical convergence and statistical boundedness of a sequence in a cone metric space. Recently, Sakaoğlu and Yurdakadim [29] have introduced the concepts of quasi-statistical convergence. The notion of quasi I-statistical convergence for triple and multiple index sequences in cone metric spaces on topological vector spaces is introduced in this study, and we also examine certain theorems connected to quasi I-statistically convergent multiple sequences. Finally, we will provide some findings based on these theorems.

Open access

# The Lower Bipartite Number of a Graph

Mathematica Pannonica
Authors:
Anna Bachstein
and
Wayne Goddard

For a graph G, we define the lower bipartite number LB(G) as the minimum order of a maximal induced bipartite subgraph of G. We study the parameter, and the related parameter bipartite domination, providing bounds both in general graphs and in some graph families. For example, we show that there are arbitrarily large 4-connected planar graphs G with LB(G) = 4 but a 5-connected planar graph has linear LB(G). We also show that if G is a maximal outerplanar graph of order n, then LB(G) lies between (n + 2)/3 and 2 n/3, and these bounds are sharp.

Open access

# Generalized Forms of an Overconstrained Sliding Mechanism Consisting of Two Congruent Tetrahedra

Studia Scientiarum Mathematicarum Hungarica
Authors:
Endre Makai Jr.
and
Tibor Tarnai

The motions of a bar structure consisting of two congruent tetrahedra are investigated, whose edges in their basic position are the face diagonals of a rectangular parallelepiped. The constraint of the motion is the following: the originally intersecting edges have to remain coplanar. All finite motions of our bar structure are determined. This generalizes our earlier work, where we did the same for the case when the rectangular parallelepiped was a cube. At the end of the paper we point out three further possibilities to generalize the question about the cube, and give for them examples of finite motions.

Restricted access

# Random Walks on the Two-Dimensional K-Comb Lattice

Mathematica Pannonica
Authors:
Endre Csáki
and
Antónia Földes

We study the path behavior of the symmetric walk on some special comb-type subsets of ℤ2 which are obtained from ℤ2 by generalizing the comb having finitely many horizontal lines instead of one.

Open access

# Splitting Edge Partitions of Graphs

Mathematica Pannonica
Authors:
Balázs Király
and
Sándor Szabó

In a typical maximum clique search algorithm when optimality testing is inconclusive a forking takes place. The instance is divided into smaller ones. This is the branching step of the procedure. In order to ensure a balanced work load for the processors for parallel algorithms it is essential that the resulting smaller problems are do not overly vary in difficulty. The so-called splitting partitions of the nodes of the given graph were introduced earlier to meliorate this problem. The paper proposes a splitting partition of the edges for the same purpose. In the lack of available theoretical tools we assess the practical feasibility of constructing suboptimal splitting edge partitions by carrying out numerical experiments. While working with splitting partitions we have realized that they can be utilized as preconditioning tools preliminary to a large scale clique search. The paper will discuss this new found role of the splitting edge partitions as well.

Open access