{"title":"Finite groups in which some particular invariant subgroups are TI-subgroups or subnormal subgroups","authors":"Yifan Liu, Jiangtao Shi","doi":"10.1515/gmj-2024-2001","DOIUrl":"https://doi.org/10.1515/gmj-2024-2001","url":null,"abstract":"Let <jats:italic>A</jats:italic> and <jats:italic>G</jats:italic> be finite groups such that <jats:italic>A</jats:italic> acts coprimely on <jats:italic>G</jats:italic> by automorphisms. We prove that if every self-centralizing non-nilpotent <jats:italic>A</jats:italic>-invariant subgroup of <jats:italic>G</jats:italic> is a TI-subgroup or a subnormal subgroup, then every non-nilpotent <jats:italic>A</jats:italic>-invariant subgroup of <jats:italic>G</jats:italic> is subnormal and <jats:italic>G</jats:italic> is <jats:italic>p</jats:italic>-nilpotent or <jats:italic>p</jats:italic>-closed for any prime divisor <jats:italic>p</jats:italic> of <jats:inline-formula> <jats:alternatives> <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\"> <m:mrow> <m:mo stretchy=\"false\">|</m:mo> <m:mi>G</m:mi> <m:mo stretchy=\"false\">|</m:mo> </m:mrow> </m:math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_gmj-2024-2001_eq_0039.png\" /> <jats:tex-math>{|G|}</jats:tex-math> </jats:alternatives> </jats:inline-formula>. If every self-centralizing non-metacyclic <jats:italic>A</jats:italic>-invariant subgroup of <jats:italic>G</jats:italic> is a TI-subgroup or a subnormal subgroup, then every non-metacyclic <jats:italic>A</jats:italic>-invariant subgroup of <jats:italic>G</jats:italic> is subnormal and <jats:italic>G</jats:italic> is solvable.","PeriodicalId":55101,"journal":{"name":"Georgian Mathematical Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139590014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Generalized essential spectra involving the class of g-g-Riesz operators","authors":"Imen Ferjani, Omaima Kchaou, Bilel Krichen","doi":"10.1515/gmj-2024-2002","DOIUrl":"https://doi.org/10.1515/gmj-2024-2002","url":null,"abstract":"In this paper, we explore the spectral properties of unbounded generalized Fredholm operators acting on a non-reflexive Banach space <jats:italic>X</jats:italic>. The results are formulated in terms of some topological conditions made on <jats:italic>X</jats:italic> or on its dual <jats:inline-formula> <jats:alternatives> <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\"> <m:msup> <m:mi>X</m:mi> <m:mo>*</m:mo> </m:msup> </m:math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_gmj-2024-2002_eq_0247.png\" /> <jats:tex-math>{X^{*}}</jats:tex-math> </jats:alternatives> </jats:inline-formula>. In addition, we introduce the concept of the so-called g-g-Riesz linear operators as an extension of Riesz operators. The obtained results are used to discuss the incidence of the behavior of generalized essential spectra. Furthermore, a relation between the generalized essential spectrum and the left (resp. the right) essential spectrum by means of g-Riesz perturbation is provided.","PeriodicalId":55101,"journal":{"name":"Georgian Mathematical Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139647865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On the representation of solution for the perturbed quasi-linear controlled neutral functional-differential equation with the discontinuous initial condition","authors":"Abdeljalil Nachaoui, Tea Shavadze, Tamaz Tadumadze","doi":"10.1515/gmj-2023-2122","DOIUrl":"https://doi.org/10.1515/gmj-2023-2122","url":null,"abstract":"The analytic relation between solutions of the original Cauchy problem and a corresponding perturbed problem is established. In the representation formula of solution, the effects of the discontinuous initial condition and perturbation of the initial data are revealed.","PeriodicalId":55101,"journal":{"name":"Georgian Mathematical Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139422507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Numerical approaches for solution of hyperbolic difference equations on circle","authors":"Allaberen Ashyralyev, Fatih Hezenci, Yasar Sozen","doi":"10.1515/gmj-2023-2103","DOIUrl":"https://doi.org/10.1515/gmj-2023-2103","url":null,"abstract":"The present paper considers nonlocal boundary value problems for hyperbolic equations on the circle <jats:inline-formula> <jats:alternatives> <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\"> <m:msup> <m:mi mathvariant=\"double-struck\">T</m:mi> <m:mn>1</m:mn> </m:msup> </m:math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_gmj-2023-2103_ineq_0001.png\" /> <jats:tex-math>mathbb{T}^{1}</jats:tex-math> </jats:alternatives> </jats:inline-formula>. The first-order modified difference scheme for the numerical solution of nonlocal boundary value problems for hyperbolic equations on a circle is presented. The stability and coercivity estimates in various Hölder norms for solutions of the difference schemes are established. Moreover, numerical examples are provided.","PeriodicalId":55101,"journal":{"name":"Georgian Mathematical Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139092302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multiplicity result for a (p(x),q(x))-Laplacian-like system with indefinite weights","authors":"Khaled Kefi, Chaima Nefzi","doi":"10.1515/gmj-2023-2107","DOIUrl":"https://doi.org/10.1515/gmj-2023-2107","url":null,"abstract":"Under some suitable conditions, we show that at least three weak solutions exist for a system of differential equations involving the <jats:inline-formula> <jats:alternatives> <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\"> <m:mrow> <m:mo stretchy=\"false\">(</m:mo> <m:mrow> <m:mi>p</m:mi> <m:mo></m:mo> <m:mrow> <m:mo stretchy=\"false\">(</m:mo> <m:mi>x</m:mi> <m:mo stretchy=\"false\">)</m:mo> </m:mrow> </m:mrow> <m:mo>,</m:mo> <m:mrow> <m:mi>q</m:mi> <m:mo></m:mo> <m:mrow> <m:mo stretchy=\"false\">(</m:mo> <m:mi>x</m:mi> <m:mo stretchy=\"false\">)</m:mo> </m:mrow> </m:mrow> <m:mo stretchy=\"false\">)</m:mo> </m:mrow> </m:math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_gmj-2023-2107_eq_0108.png\" /> <jats:tex-math>{(p(x),q(x))}</jats:tex-math> </jats:alternatives> </jats:inline-formula> Laplacian-like with indefinite weights. The proof is related to the Bonanno–Marano critical theorem (<jats:italic>Appl. Anal.</jats:italic> 89 (2010), 1–10).","PeriodicalId":55101,"journal":{"name":"Georgian Mathematical Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139077826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Almost measurable functions on probability spaces","authors":"Alexander Kharazishvili","doi":"10.1515/gmj-2023-2120","DOIUrl":"https://doi.org/10.1515/gmj-2023-2120","url":null,"abstract":"The notion of (real-valued) almost measurable functions on probability spaces is introduced and some of their properties are considered. It is shown that any almost measurable function may be treated as a quasi-random variable in the sense of [A. Kharazishvili, On some version of random variables, Trans. A. Razmadze Math. Inst. 177 2023, 1, 143–146].","PeriodicalId":55101,"journal":{"name":"Georgian Mathematical Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139077822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On φ-u-S-flat modules and nonnil-u-S-injective modules","authors":"Hwankoo Kim, Najib Mahdou, El Houssaine Oubouhou","doi":"10.1515/gmj-2023-2117","DOIUrl":"https://doi.org/10.1515/gmj-2023-2117","url":null,"abstract":"This paper introduces and studies the ϕ-u-<jats:italic>S</jats:italic>-flat (resp., nonnil-u-<jats:italic>S</jats:italic>-injective) modules, which are a generalization of both ϕ-flat modules and u-<jats:italic>S</jats:italic>-flat modules (resp., both nonnil-injective modules and u-<jats:italic>S</jats:italic>-injective modules). We give the Cartan–Eilenberg–Bass theorem for nonnil-u-<jats:italic>S</jats:italic>-Noetherian rings. Finally, we offer some new characterizations of the ϕ-von Neumann regular ring.","PeriodicalId":55101,"journal":{"name":"Georgian Mathematical Journal","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139077993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}