<abstract xmlns="http://www.w3.org/1999/xhtml">

In this paper we deal with the discretization of the second order wave equation by the implicit Euler scheme for the time and the spectral method for the space. We prove that the time semi discrete and the full discrete problems are well posed. We show an optimal error estimates related to both variables time and space.
</abstract>

Department of Mathematics, College of Science

The spectral discretization of the second-order wave equation

<abstract xmlns="http://www.w3.org/1999/xhtml">

To model statistical data coming from two di erent distributions, Cooray and Ananda [1] introduced a composite (two-spliced) Lognormal-Pareto model, that was further extended by Scollnik [9] and fitted to insurance data. Inspired by these studies, more general three-spliced composite models are considered in this work, built by joining three di erent distributions. In particular, the study is focused on the three-spliced Exponential-Lognormal-Pareto distribution. The main characteristics of this model, as well as statistical inference are discussed. The parameters estimation is illustrated on random generated data.
</abstract>

On the three-spliced Exponential-Lognormal-Pareto distribution

<abstract xmlns="http://www.w3.org/1999/xhtml">

Using the technique of enriching contractive type mappings, we introduce a more general concept of enriched Ćirić-Reich-Rus contraction than the one studied in [Berinde, V.; Păcurar, M. Fixed point theorems for enriched Ćirić-Reich-Rus contractions in Banach spaces and convex metric spaces. <italic>Carpathian J. Math.</italic> <bold>37</bold> (2021), no. 2, 173–184.] and provide convergence results for the Krasnoselskij iterative algorithm used to approximate their fixed points. Examples to illustrate the effectiveness of the new results as well as comparison to other classes of contractive type mappings existing in literature are also presented. In this context, we also conclude that Ćirić-Reich-Rus contractions form a class of unsaturated mappings.
</abstract>

Academy of Romanian Scientists and Department of Mathematics and Computer Science

Technical University of Cluj-Napoca, North University Centre at Baia Mare

Department of Economics and Business Administration in German Language, Faculty of Economics and Business Administration

A new class of unsaturated mappings: Ćirić-Reich-Rus contractions

<abstract xmlns="http://www.w3.org/1999/xhtml">

We inquire whether there are some fundamental interpretations of elementary inequalities in terms of curvature of a three-dimensional smooth hypersurface in the four-dimensional real ambient space. The main outcome of our exploration is a perspective of regarding the natural substance of some mathematical inequalities, which represent important physical quantities.
</abstract>

Are There Any Natural Physical Interpretations for Some Elementary Inequalities?

<abstract xmlns="http://www.w3.org/1999/xhtml">

In this paper, we study the link between finite-dimensional Zinbiel algebras and combinatorial structures or (pseudo)digraphs determining which configurations are associated with those algebras. Some properties of Zinbiel algebras that can be read from their associated combinatorial structures are studied. We also analyze the isomorphism classes for each configuration associated with these algebras providing a new method to classify them and we compare our results with the current classifications of 2- and 3-dimensional Zinbiel algebras. We also obtain the 3-vertices combinatorial structures associated with such algebras. In order to complement the theoretical study, we have designed and performed the implementation of an algorithm which constructs and draws the (pseudo)digraph associated with a given Zinbiel algebra and, conversely, another procedure to test if a given combinatorial structure is associated with some Zinbiel algebra.
</abstract>

Dpto. de Economía, Métodos Cuantitativos e Historia Económica

Finite-dimensional Zinbiel algebras and combinatorial structures

<abstract xmlns="http://www.w3.org/1999/xhtml">

In the present paper, a numerical scheme is discussed to solve one-dimensional nonlinear diffusion equation of fractional order in which collocation is performed using the Lucas operational matrix. Since the spectral collocation method is used in the proposed method, therefore the residual, initial and boundary conditions of the presented problem are collocated at fixed collocation points. The result is a system of nonlinear equations that can be solved by using Newton’s method. Through error analysis and application to some existing problems, the accuracy of the method is confirmed. The obtained results are presented in tabular forms, which clearly show the higher accuracy of the proposed method. The variations of the solute profile of the proposed model are shown graphically due to the presence or absence of advection and reaction terms for different particular cases.
</abstract>

Ovidius University of Constanta Bd. Mamaia 124

Operational matrix method to solve nonlinear reaction-advection-diffusion equation in fractional order system

<abstract xmlns="http://www.w3.org/1999/xhtml">

Life expectancy models are highly important, as they indicate the populations health. The present models consider several types of factors, and by analyzing them we extend the formulae to new, mixed types in order to create particular representations that are beneficial for creating future results and estimations.
</abstract>

Some general Gompertz and Gompertz-Makeham life expectancy models

<abstract xmlns="http://www.w3.org/1999/xhtml">

The advantage of various fuzzy normed spaces is to analyse impreciseness and ambiguity that arise in modelling problems. In this paper, various classical stabilities of a new hexic functional equation in di erent fuzzy spaces like fuzzy Banach space, Felbin’s fuzzy Banach space and intuitionistic fuzzy Banach space are presented, concerning the Ulam’s theory of stabilities of equations. To validate the stability results, experimental results are presented. Also, a comparative study of the results obtained in this investigation are provided.
</abstract>

University of Technology and Applied Sciences

Fuzzy stabilities of a new hexic functional equation in various spaces

<abstract xmlns="http://www.w3.org/1999/xhtml">

In our paper we describe the corresponding dynamic mathematical models to perform a comparative analysis of the reliability of two types of networks: serial-parallel and parallel-serial when the number of subnetworks is constant and the numbers of units in each sub-network are Power Series Distributed (PSD) random variables (r.v.), but also when the lifetimes are independent, identically distributed r.v. We shows that the lifetime distributions of such kind of networks leads us to two new families of distributions called Min(Max-PSD) and Max(Min-PSD) distributions. The formulas for calculating the reliability of the related networks it was deduced too. Su cient conditions have been formulated for the serial-parallel network to always be more reliable than the parallel-serial network. Some graphically illustrated examples have been provided.
</abstract>

Department of Software Engeneering and Authomatics

Min(Max-PSD) and Max(Min-PSD) as lifetime distributions in Network’s Reliability

<abstract xmlns="http://www.w3.org/1999/xhtml">

In this paper, we consider the partition function <italic>Q</italic>(<italic>n</italic>) counting the partitions of <italic>n</italic> into distinct parts and investigate congruence identities of the form
<disp-formula>
<alternatives>
<graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/j_auom-2022-0040_eq_001.png"></graphic>
<math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="block"><mrow><mi>Q</mi><mrow><mo>(</mo><mrow><mi>p</mi><mo>⋅</mo><mi>n</mi><mo>+</mo><mfrac><mrow><msup><mrow><mi>p</mi></mrow><mn>2</mn></msup><mo>-</mo><mn>1</mn></mrow><mrow><mn>24</mn></mrow></mfrac></mrow><mo>)</mo></mrow><mo>≡</mo><mn>0</mn><mi> </mi><mi> </mi><mi> </mi><mrow><mo>(</mo><mrow><mo>mod</mo><mn>4</mn></mrow><mo>)</mo></mrow><mo>,</mo></mrow></math>
<tex-math>Q\left( {p \cdot n + {{{p^2} - 1} \over {24}}} \right) \equiv 0\,\,\,\left( {\bmod 4} \right),</tex-math>
</alternatives>
</disp-formula>
where <italic>p</italic> ⩾ 5 is a prime.
</abstract>

Ramanujan-type congruences modulo 4 for partitions into distinct parts

AHEAD OF PRINT

Volume 31 (2023): Issue 3 (September 2023)

Volume 31 (2023): Issue 2 (March 2023)

Volume 31 (2023): Issue 1 (January 2023)

Volume 30 (2022): Issue 3 (September 2022)

Volume 30 (2022): Issue 2 (May 2022)

Volume 30 (2022): Issue 1 (February 2022)

Volume 29 (2021): Issue 3 (November 2021)

Volume 29 (2021): Issue 2 (June 2021)

Volume 29 (2021): Issue 1 (March 2021)

Volume 28 (2020): Issue 3 (December 2020)

Volume 28 (2020): Issue 2 (July 2020)

Volume 28 (2020): Issue 1 (March 2020)

Volume 27 (2019): Issue 3 (December 2019)

Volume 27 (2019): Issue 2 (June 2019)

Volume 27 (2019): Issue 1 (March 2019)

Volume 26 (2018): Issue 3 (December 2018)

Volume 26 (2018): Issue 2 (July 2018)

Volume 26 (2018): Issue 1 (March 2018)

Volume 25 (2017): Issue 3 (December 2017)

Volume 25 (2017): Issue 2 (July 2017)

Volume 25 (2017): Issue 1 (January 2017)

Volume 24 (2016): Issue 3 (November 2016)

Volume 24 (2016): Issue 2 (June 2016)

Volume 24 (2016): Issue 1 (January 2016)

Volume 23 (2015): Issue 3 (November 2015)

Volume 23 (2015): Issue 2 (June 2015)

Volume 23 (2015): Issue 1 (January 2015)

Volume 22 (2014): Issue 3 (September 2014)

Volume 22 (2014): Issue 2 (June 2014)

Volume 22 (2014): Issue 1 (March 2014)

Volume 21 (2013): Issue 3 (November 2013)

Volume 21 (2013): Issue 2 (June 2013)

Volume 21 (2013): Issue 1 (March 2013)

Volume 20 (2012): Issue 3 (December 2012)

Volume 20 (2012): Issue 2 (June 2012) Proceedings of the 10th International Workshop on Differential Geometry and its Applications

Volume 20 (2012): Issue 1 (May 2012)

Analele ştiinţifice ale Universităţii "Ovidius" Constanţa. Seria Matematică

This journal is devoted to pure and applied mathematics. Papers from other fields of science may be accepted if they present interesting original mathematical results. Starting 2008 the journal has been selected for coverage in the Science Citation Index Expanded (SCIE) - Thomson Reuters and from 2011 the journal is included in Master Journal List, with increasing IF.  This journal is also included in many digital directories of open resources in mathematics as EMIS ELibM, AMS Digital Mathematics Registry, Intute (UK), DOAJ (Lund University Libraries).  Why subscribe and read   High quality articles authored by researchers from all over the word  The articles are reviewed/indexed by Zentralblatt fur Mathematik and Mathematical Reviews   Why submit   Each paper is reviewed by at least two specialists in the field  An. Stiint. Univ. Ovidius Constanta, Ser. Mat. Is an open access journal  This journal is a blind Peer Review journal. During the Peer Review process, the referees make a critical evaluation of the submitted paper and an explicit recommendation to accept or reject the paper for publication. In many cases, referees recommend acceptance (or re-evaluation) subject to a revision, and provide explicit guidelines for the author(s) to follow.  The process of refereeing normally takes 3-4 months. Referees are not supposed to communicate directly with the authors. All communications are through the editors.   Target Group  - researchers in all fields of pure and applied mathematics  Rejection Rate   More than 75%   Archiving  Sciendo archives the contents of this journal in Portico - digital long-term preservation service of scholarly books, journals and collections.  Plagiarism Policy  The editorial board is participating in a growing community of Similarity Check System's users in order to ensure that the content published is original and trustworthy. Similarity Check is a medium that allows for comprehensive manuscripts screening, aimed to eliminate plagiarism and provide a high standard and quality peer-review process. P&gt; 