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# The Principal Fibre Bundle on Lorentzian Almost R-para Contact Structure

Mathematica Pannonica
Authors:
Lovejoy S. Das
and

The purpose of this paper is to study the principal fibre bundle (P, M, G, π p ) with Lie group G, where M admits Lorentzian almost paracontact structure (Ø, ξ p , η p , g) satisfying certain condtions on (1, 1) tensor field J, indeed possesses an almost product structure on the principal fibre bundle. In the later sections, we have defined trilinear frame bundle and have proved that the trilinear frame bundle is the principal bundle and have proved in Theorem 5.1 that the Jacobian map π * is the isomorphism.

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# Some Zero-One Linear Programming Reformulations for the Maximum Clique Problem

Mathematica Pannonica
Authors:
Ákos Beke
,
Sándor Szabó
, and
Bogdán Zavalnij

Many combinatorial optimization problems can be expressed in terms of zero-one linear programs. For the maximum clique problem the so-called edge reformulation is applied most commonly. Two less frequently used LP equivalents are the independent set and edge covering set reformulations. The number of the constraints (as a function of the number of vertices of the ground graph) is asymptotically quadratic in the edge and the edge covering set LP reformulations and it is exponential in the independent set reformulation, respectively. F. D. Croce and R. Tadei proposed an approach in which the number of the constraints is equal to the number of the vertices. In this paper we are looking for possible tighter variants of these linear programs.

Open access

# Dispersion’s Uncertainty Principles Associated with the Directional short-time Fourier Transform

Studia Scientiarum Mathematicarum Hungarica
Authors:
Siwar Hkimi
,
Hatem Mejjaoli
, and
Slim Omri

We introduce the directional short-time Fourier transform for which we prove a new Plancherel’s formula. We also prove for this transform several uncertainty principles as Heisenberg inequalities, logarithmic uncertainty principle, Faris–Price uncertainty principles and Donoho–Stark’s uncertainty principles.

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# The Extended Beta Generator of Distributions: Properties and Applications

Studia Scientiarum Mathematicarum Hungarica
Authors:
Gauss M. Cordeiro
,
Thiago G. Ramires
,
Edwin M. M. Ortega
, and
Rodrigo R. Pescim

We deﬁne the extended beta family of distributions to generalize the beta generator pioneered by Eugene et al. [10]. This paper is cited in at least 970 scientiﬁc articles and extends more than ﬁfty well-known distributions. Any continuous distribution can be generalized by means of this family. The proposed family can present greater ﬂexibility to model skewed data. Some of its mathematical properties are investigated and maximum likelihood is adopted to estimate its parameters. Further, for different parameter settings and sample sizes, some simulations are conducted. The superiority of the proposed family is illustrated by means of two real data sets.

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# Extended Cauchy–Schwarz Inequality and its Application for the two-Class Fisher Discriminant Analysis

Studia Scientiarum Mathematicarum Hungarica
Authors:
Maciej Sablik
and
Katarzyna Stapor

We present the sufficient condition for a classical two-class problem from Fisher discriminant analysis has a solution. Actually, the solution was presented up to our knowledge with a necessary condition only. We use an extended Cauchy–Schwarz inequality as a tool.

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# Morrey Spaces Related to Schrödinger Operators with Certain Nonnegative Potentials and Littlewood–Paley–Stein Functions on the Heisenberg groups

Studia Scientiarum Mathematicarum Hungarica
Author:
Hua Wang

Let be a Schrödinger operator on the Heisenberg group $ℍ n$ , where $Δ ℍ n$ is the sublaplacian on $ℍ n$ and the nonnegative potential V belongs to the reverse Hölder class $B q$ with $q ∈ [ Q / 2 , + ∞ )$ . Here is the homogeneous dimension of $ℍ n$ . Assume that ${ e − s L } s > 0$ is the heat semigroup generated by $L$ . The Lusin area integral $S L ; α$ and the Littlewood–Paley–Stein function $g λ , L *$ associated with the Schrödinger operator $L$ are deﬁned, respectively, by

$S L ; α ( f ) ( u ) : = ∬ Γ α ( u ) s d d s e − s L f ( υ ) 2 d υ d s s Q / 2 + 1 1 / 2 ,$

where

$Γ α ( u ) : = { ( υ , s ) ∈ ℍ n × ( 0 , + ∞ ) : u − 1 υ < α s } ,$

and

Where $λ ∈ (0,+ ∞ )$ is a parameter. In this article, the author shows that there is a relationship between $S L ; α$ and the operator $g λ , L *$ and for any $1 ≤ p < ∞$ , the following inequality holds true:

$S L ; 2 j ( f ) L p ℍ n ≤ C 2 j Q / 2 + 2 j Q / p s L ( f ) L p ( ℍ n ) .$

Based on this inequality and known results for the Lusin area integral $S L ; 1$ , the author establishes the strong-type and weak-type estimates for the Littlewood–Paley–Stein function $g λ , L *$ on $L p ( ℍ n )$ . In this article, the author also introduces a class of Morrey spaces associated with the Schrödinger operator $L$ on $ℍ n$ . By using some pointwise estimates of the kernels related to the nonnegative potential V, the author establishes the boundedness properties of the operator $g λ , L *$ acting on the Morrey spaces for an appropriate choice of $λ > 0$ . It can be shown that the same conclusions hold for the operator $g λ , L *$ on generalized Morrey spaces as well.

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# Some Classes of Polynomials Satisfying Sendov’s Conjecture

Studia Scientiarum Mathematicarum Hungarica
Authors:
,
, and
Robert Bentley Gardner

In this paper, a relationship between the zeros and critical points of a polynomial p(z) is established. The relationship is used to prove Sendov’s conjecture in some special cases.

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# Stationary Solution of a Fluid Queue Driven by a Queue with Chain Sequence Rates and Controlled Input

Studia Scientiarum Mathematicarum Hungarica
Authors:
Susairaj Sophia
and
Babu Muthu Deepika

A ﬂuid queueing system in which the ﬂuid ﬂow in to the buffer is regulated by the state of the background queueing process is considered. In this model, the arrival and service rates follow chain sequence rates and are controlled by an exponential timer. The buffer content distribution along with averages are found using continued fraction methodology. Numerical results are illustrated to analyze the trend of the average buffer content for the model under consideration. It is interesting to note that the stationary solution of a ﬂuid queue driven by a queue with chain sequence rates does not exist in the absence of exponential timer.

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# A Type of Orthonormal bases on 2-*-inner Product Spaces

Studia Scientiarum Mathematicarum Hungarica
Authors:
,
Tayebe Lal Shateri
, and

In this paper, we deﬁne an orthonormal basis for 2-*-inner product space and obtain some useful results. Moreover, we introduce a 2-norm on a dense subset of a 2-*-inner product space. Finally, we obtain a version of the Selberg, Buzano’s and Bessel inequality and its results in an A-2-inner product space.

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# Another characterization of congruence distributive varieties

Studia Scientiarum Mathematicarum Hungarica
Author:
Paolo Lipparini

## Abstract

We provide a Maltsev characterization of congruence distributive varieties by showing that a variety 𝓥 is congruence distributive if and only if the congruence identity $α ∩ ( β ∘ γ ∘ β ) ⊆ _ α β ∘ γ ∘ α β ∘ γ$ … (k factors) holds in 𝓥, for some natural number k.

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