{"title":"Diophantine sets and Dirichlet improvability","authors":"Antoine Marnat","doi":"10.2140/moscow.2022.11.189","DOIUrl":"https://doi.org/10.2140/moscow.2022.11.189","url":null,"abstract":"This note pushes further the discussion about relations between Dirichlet improvable, badly approximable and singular points held in recent joint work with Beresnevich, Guan, Velani and Ramirez, by considering Diophantine sets extending the notion of badly approximability.","PeriodicalId":36590,"journal":{"name":"Moscow Journal of Combinatorics and Number Theory","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47914600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An improved convergence case for Diophantine approximations on IFS fractals","authors":"Itamar Cohen-Matalon","doi":"10.2140/moscow.2023.12.97","DOIUrl":"https://doi.org/10.2140/moscow.2023.12.97","url":null,"abstract":"The objective of this paper is to (partially) address the issue of finding an analogue to Khintchine's theorem for IFS Fractals. We study the convergence case for Diophantine approximations, and show an improved result for higher dimensions. This matter has been previously studied by Pollington and Velani in arXiv:math/0401149. Pollington and Velani show a similar result to the one in this paper (a Khinchine convergence case) and we shall show how our result is an improvement in the higher dimensional cases.","PeriodicalId":36590,"journal":{"name":"Moscow Journal of Combinatorics and Number Theory","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48036432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A generalization of a theorem of White","authors":"V. Batyrev, Johannes Hofscheier","doi":"10.2140/moscow.2021.10.281","DOIUrl":"https://doi.org/10.2140/moscow.2021.10.281","url":null,"abstract":"","PeriodicalId":36590,"journal":{"name":"Moscow Journal of Combinatorics and Number Theory","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42144987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Visibility properties of spiral sets","authors":"F. Adiceam, Ioannis Tsokanos","doi":"10.2140/moscow.2022.11.149","DOIUrl":"https://doi.org/10.2140/moscow.2022.11.149","url":null,"abstract":". A spiral in R d +1 is defined as a set of the form { d +1 √ n · u n } n ≥ 1 , where ( u n ) n ≥ 1 is a spherical sequence. Such point sets have been extensively studied, in particular in the planar case d = 1, as they then serve as natural models describing phyllotactic structures (i.e. structures representing configurations of leaves on a plant stem). Recent progress in this theory provides a fine analysis of the distribution of spirals (e.g., their covering and packing radii). Here, various concepts of visiblity from discrete geometry are employed to characterise density properties of such point sets. More pre-cisely, necessary an sufficient conditions are established for a spiral to be (1) an orchard (a “homogeneous” density property defined by P`olya), (2) a uniform orchard (a concept introduced in this work), (3) a set with no visible point (implying that the point set is dense enough in a suitable sense) and (4) a dense forest (a quantitative and uniform refinement of the previous concept).","PeriodicalId":36590,"journal":{"name":"Moscow Journal of Combinatorics and Number Theory","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41415488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Improved constants for effective irrationality measures from hypergeometric functions","authors":"P. Voutier","doi":"10.2140/moscow.2022.11.161","DOIUrl":"https://doi.org/10.2140/moscow.2022.11.161","url":null,"abstract":". In this paper, we simplify and improve the constant, c , that appears in effective irrationality measures, | ( a/b ) m/n − p/q | > c | q | − ( κ +1) , obtained from the hypergeometric method for a/b near 1. The dependence of c on both | a | in our result is best possible (as is the dependence on n in many cases). For some applications, the dependence of this constant on | a | becomes important. We also establish some new inequalities for hypergeometric functions that are useful in other diophantine settings.","PeriodicalId":36590,"journal":{"name":"Moscow Journal of Combinatorics and Number Theory","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44617890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On the representation of integers by binary\u0000forms defined by means of the relation (x + yi)n= Rn(x,y) + Jn(x,y)i","authors":"A. Mosunov","doi":"10.2140/moscow.2022.11.71","DOIUrl":"https://doi.org/10.2140/moscow.2022.11.71","url":null,"abstract":"Let F be a binary form with integer coefficients, degree d ≥ 3 and nonzero discriminant. Let RF (Z) denote the number of integers of absolute value at most Z which are represented by F . In 2019 Stewart and Xiao proved that RF (Z) ∼ CFZ 2/d for some positive number CF . We compute CRn and CJn for the binary forms Rn(x, y) and Jn(x, y) defined by means of the relation (x+ yi) = Rn(x, y) + Jn(x, y)i, where the variables x and y are real.","PeriodicalId":36590,"journal":{"name":"Moscow Journal of Combinatorics and Number Theory","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42610340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}