{"title":"On a Linear Form in the Ordinates of Zeros of the Riemann Zeta Function","authors":"E. D. Yudelevich","doi":"10.1134/s0001434624010103","DOIUrl":"https://doi.org/10.1134/s0001434624010103","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p> We obtain an asymptotic formula for the sum </p><span>$$H=sum_{0<gamma_kle T,,1le kle 4}h(gamma_1+gamma_2-gamma_3-gamma_4),$$</span><p> where the <span>(gamma_k)</span> run over the imaginary parts of nontrivial zeros of the Riemann zeta function with multiplicities taken into account and the function <span>(h)</span> belongs to some special class of functions in <span>(L^1(mathbb R))</span>. </p>","PeriodicalId":18294,"journal":{"name":"Mathematical Notes","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140805212","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":"Periodic Gibbs Measures and Their Extremality for the HC-Blume–Capel Model in the Case of a Wand with a Chemical Potential on a Cayley Tree","authors":"N. M. Khatamov","doi":"10.1134/s0001434624010085","DOIUrl":"https://doi.org/10.1134/s0001434624010085","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p> Periodic Gibbs measures for the HC-Blume–Capel model with a chemical potential with parameters <span>((theta,eta))</span> on a Cayley tree in the case of a wand graph are studied. We prove that in this case for <span>(theta^3leeta)</span> there exist precisely three periodic Gibbs measures, all of which are translation-invariant, while for <span>(theta^3>eta)</span> there exist precisely three periodic Gibbs measures, one of which is translation-invari The (non)extremality of these measures is also studied. </p>","PeriodicalId":18294,"journal":{"name":"Mathematical Notes","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140805291","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":"The Strong Convexity Supporting Condition and the Lipschitz Condition for the Metric Projection","authors":"M. V. Balashov, K. Z. Biglov","doi":"10.1134/s0001434624010152","DOIUrl":"https://doi.org/10.1134/s0001434624010152","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p> We prove that the strong convexity supporting condition is typical for an arbitrary convex compact set in <span>(mathbb R^n)</span>. It is shown that, in a certain sense for almost all points, the metric projection onto a convex compact set satisfies the Lipschitz condition with Lipschitz constant strictly less than 1. This condition characterizes the strong convexity supporting condition. The linear convergence of the alternating projection method for a convex compact set with the strong convexity supporting condition and for a proximally smooth set is proved under a certain relation between the constant in the strong convexity supporting condition and the proximal smoothness constant. </p>","PeriodicalId":18294,"journal":{"name":"Mathematical Notes","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140805293","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 Well-Posedness of an Initial–Boundary Value Problem for a Degenerate Heat Equation","authors":"A. R. Zainullov, K. B. Sabitov","doi":"10.1134/s0001434624010188","DOIUrl":"https://doi.org/10.1134/s0001434624010188","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p> The well-posedness of an initial–boundary value problem for a model parabolic equation with two power-law degeneration lines is studied. Two initial–boundary value problems depending on the degeneracy exponents are stated, and uniqueness and existence theorems are proved. The solutions of these problems are constructed in closed form. </p>","PeriodicalId":18294,"journal":{"name":"Mathematical Notes","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140805352","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":"Bernstein Inequality for the Riesz Derivative of Order $$0<alpha<1$$ of Entire Functions of Exponential Type in the Uniform Norm","authors":"A. O. Leont’eva","doi":"10.1134/s000143462401019x","DOIUrl":"https://doi.org/10.1134/s000143462401019x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p> We consider Bernstein’s inequality for the Riesz derivative of order <span>(0<alpha<1)</span> of entire functions of exponential type in the uniform norm on the real line. For this operator, the corresponding interpolation formula is obtained; this formula has nonequidistant nodes. Using this formula, the sharp Bernstein inequality is obtained for all <span>(0<alpha<1)</span>; namely, the extremal entire function and the sharp constant are written out. </p>","PeriodicalId":18294,"journal":{"name":"Mathematical Notes","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140805218","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":"Implementation of Linear Boolean Functions by Self-Correcting Circuits of Unreliable Logic Gates","authors":"K. A. Popkov","doi":"10.1134/s0001434624010073","DOIUrl":"https://doi.org/10.1134/s0001434624010073","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p> We prove that if a Boolean function essentially depends on at least two variables, then it cannot be implemented by a circuit that consists of unreliable gates with at most two inputs each and is self-correcting with respect to at least some faults of an arbitrary number of gates. In view of the previous results, it suffices to establish this fact for linear functions. </p>","PeriodicalId":18294,"journal":{"name":"Mathematical Notes","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140805220","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":"Two Contrasting Examples of Multidimensional Differential Systems with Lyapunov Extreme Instability","authors":"A. A. Bondarev","doi":"10.1134/s0001434624010036","DOIUrl":"https://doi.org/10.1134/s0001434624010036","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p> Using specific examples, we constructively show that, in dimensions greater than <span>(1)</span>, the Lyapunov extreme instability of a differential system, i.e., the property that the phase curves of all nonzero solutions starting sufficiently close to zero leave any prescribed compact set, does not imply that these solutions go arbitrarily far away from zero in the sense of Perron or in the upper-limit sense as <span>(ttoinfty)</span>. Namely, we construct two Lyapunov extremely unstable systems such that all solutions of the first system tend to zero, while the solutions of the second system are divided into two types: all nonzero solutions starting in the closed unit ball tend to infinity in norm, and all the other solutions tend to zero. Further, both systems constructed in the paper have zero first approximation along the zero solution. </p>","PeriodicalId":18294,"journal":{"name":"Mathematical Notes","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140806821","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":"Extremal Interpolation in the Mean in the Space $$L_1(mathbb R)$$ with Overlapping Averaging Intervals","authors":"V. T. Shevaldin","doi":"10.1134/s0001434624010097","DOIUrl":"https://doi.org/10.1134/s0001434624010097","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p> On a uniform grid on the real axis <span>(mathbb R)</span>, we study the Yanenko–Stechkin–Subbotin problem of extremal function interpolation in the mean in the space <span>(L_1(mathbb R))</span> of two-way real sequences with the least value of the norm of a linear formally s This problem is considered for the class of sequences for which the generalized finite differences of order <span>(n)</span> corresponding to the operator <span>(mathcal L_n)</span> are bounded in the space <span>(l_1)</span>. In this paper, the least value of the norm is calculated exactly if the grid step <span>(h)</span> and the averaging step <span>(h_1)</span> of the function to be interpolated in the mean are related by the inequalities <span>(h<h_1le 2h)</span>. The paper is a continuation of the research by Yu. N. Subbotin and the author in this problem, initiated by Yu. N. Subbotin in 1965. The result obtained is new, in particular, for the <span>(n)</span>-times differentiation operator <span>(mathcal L_n(D)=D^n)</span>. </p>","PeriodicalId":18294,"journal":{"name":"Mathematical Notes","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140882728","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":"Uniform Rational Approximation of Even and Odd Continuations of Functions","authors":"T. S. Mardvilko","doi":"10.1134/s0001434624010206","DOIUrl":"https://doi.org/10.1134/s0001434624010206","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p> The behavior of the best rational approximations of an odd continuation of a function is studied. It is shown that without additional conditions on the smoothness of the function, it is impossible to estimate the best rational approximation of the odd continuation of the function on <span>([-1,1])</span> in terms of the best rational approximation of the original function on <span>([0,1])</span>. A sharp upper bound is found for the best rational approximations of an even (odd) continuation of a function in terms of an odd (even) continuation and an extremal Blaschke product. </p>","PeriodicalId":18294,"journal":{"name":"Mathematical Notes","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140882609","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":"Ricci Solitons on Generalized Sasakian-Space-Forms with Kenmotsu Metric","authors":"Savita Rani, Ram Shankar Gupta","doi":"10.1134/s0001434624010231","DOIUrl":"https://doi.org/10.1134/s0001434624010231","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p> We study Ricci solitons and <span>(ast)</span>-Ricci solitons on generalized Sasakian-space-forms (GSSF) <span>(M^{2n+1} (f_1, f_2, f_3))</span> with parallel <span>(ast)</span>-Ricci tensor. We find that if GSSF <span>(M^{2n+1} (f_1, f_2, f_3))</span> with Kenmotsu metric admits a Ricci soliton or a <span>(ast)</span>-Ricci soliton, then <span>(f_1=-1)</span> and <span>(f_2=f_3=0)</span>. Moreover, the Ricci soliton is expanding, and the <span>(ast)</span>-Ricci soliton is steady. Further, we provide some examples. </p>","PeriodicalId":18294,"journal":{"name":"Mathematical Notes","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140882539","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}