Three determinants for symmetric and skew-symmetric matrices are explicitly evaluated, in closed form, as circular products. One of them gives a solution to a problem proposed by Dzhumadil’daev [ Amer. Math. Monthly 129 (2022) 486].
{"title":"Three determinants evaluated in circular products","authors":"Shuling Gao, W. Chu","doi":"10.47443/cm.2022.029","DOIUrl":"https://doi.org/10.47443/cm.2022.029","url":null,"abstract":"Three determinants for symmetric and skew-symmetric matrices are explicitly evaluated, in closed form, as circular products. One of them gives a solution to a problem proposed by Dzhumadil’daev [ Amer. Math. Monthly 129 (2022) 486].","PeriodicalId":48938,"journal":{"name":"Contributions To Discrete Mathematics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79576173","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}
A set S of vertices in a connected graph G is an irregular dominating set if the vertices of S can be labeled with distinct positive integers in such a way that for every vertex u of G , there is a vertex v ∈ S such that the distance from u to v is the label assigned to v . If for every vertex v ∈ S , there is a vertex u of G such that v is the only vertex of S whose distance to u is the label of v , then S is a minimal irregular dominating set. A graph H is an irregular domination graph if there exists a graph G with a minimal irregular dominating set S such that H is isomorphic to the subgraph G [ S ] of G induced by S . We determine all paths and cycles that are irregular domination graphs as well as the familiar graphs of ladders and prisms, which are Cartesian products of K 2 with paths and cycles, respectively. Other results and problems are also presented on this topic.
{"title":"Irregular domination graphs","authors":"Caryn Mays, Ping Zhang","doi":"10.47443/cm.2022.033","DOIUrl":"https://doi.org/10.47443/cm.2022.033","url":null,"abstract":"A set S of vertices in a connected graph G is an irregular dominating set if the vertices of S can be labeled with distinct positive integers in such a way that for every vertex u of G , there is a vertex v ∈ S such that the distance from u to v is the label assigned to v . If for every vertex v ∈ S , there is a vertex u of G such that v is the only vertex of S whose distance to u is the label of v , then S is a minimal irregular dominating set. A graph H is an irregular domination graph if there exists a graph G with a minimal irregular dominating set S such that H is isomorphic to the subgraph G [ S ] of G induced by S . We determine all paths and cycles that are irregular domination graphs as well as the familiar graphs of ladders and prisms, which are Cartesian products of K 2 with paths and cycles, respectively. Other results and problems are also presented on this topic.","PeriodicalId":48938,"journal":{"name":"Contributions To Discrete Mathematics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81952655","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}
Let X ⊂ P r be a projective embedded variety defined over a field K . Results relating maximum and generic X -rank of points of P r ( K ) and P r ( L ) are given, where L is a field containing K . Some of these results are algebraically closed for K and L . In other results (e.g. on the cactus rank), L is a finite extension of K .
设X∧P r是定义在域K上的一个射影内嵌变量。给出了P r (K)和P r (L)的点的极大值和一般X -秩的结果,其中L是包含K的域。其中一些结果对K和L在代数上是封闭的。在其他结果中(例如仙人掌的排名),L是K的有限扩展。
{"title":"X-ranks for embedded varieties and extensions of fields","authors":"E. Ballico","doi":"10.47443/cm.2022.021","DOIUrl":"https://doi.org/10.47443/cm.2022.021","url":null,"abstract":"Let X ⊂ P r be a projective embedded variety defined over a field K . Results relating maximum and generic X -rank of points of P r ( K ) and P r ( L ) are given, where L is a field containing K . Some of these results are algebraically closed for K and L . In other results (e.g. on the cactus rank), L is a finite extension of K .","PeriodicalId":48938,"journal":{"name":"Contributions To Discrete Mathematics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73885832","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}
In this paper, using a generalized integral operator, new Hermite-Hadamard type inequalities are obtained for differentiable modified ( h, m ) -convex functions of the second type.
{"title":"On the Hermite-Hadamard type inequalities involving generalized integrals","authors":"J. E. Valdés","doi":"10.47443/cm.2022.020","DOIUrl":"https://doi.org/10.47443/cm.2022.020","url":null,"abstract":"In this paper, using a generalized integral operator, new Hermite-Hadamard type inequalities are obtained for differentiable modified ( h, m ) -convex functions of the second type.","PeriodicalId":48938,"journal":{"name":"Contributions To Discrete Mathematics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72471718","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}
The aim of this short note is to establish an elegant sum involving central binomial coefficients, due to L´aszl´o [ Amer. Math. Monthly 108 (2001) 851–855], via a hypergeometric series approach.
这篇短文的目的是建立一个涉及中心二项式系数的优雅和,由于L ' aszl ' o [Amer]。数学。月刊108(2001)851-855],通过超几何级数方法。
{"title":"A short derivation of an elegant sum involving central binomial coefficients due to Laszlo via a hypergeometric series approach","authors":"D. Lim, A. Rathie","doi":"10.47443/cm.2022.025","DOIUrl":"https://doi.org/10.47443/cm.2022.025","url":null,"abstract":"The aim of this short note is to establish an elegant sum involving central binomial coefficients, due to L´aszl´o [ Amer. Math. Monthly 108 (2001) 851–855], via a hypergeometric series approach.","PeriodicalId":48938,"journal":{"name":"Contributions To Discrete Mathematics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84482879","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}
In this paper, several erroneous results appeared in the papers [T.-Y. Zhang, A.-P. Ji, F. Qi, Abstr. Appl. Anal. 2012 (2012) #560586] and [T.-Y. Zhang, M. Tunc¸, A.-P. Ji, B.-Y. Xi, Abstr. Appl. Anal. 2014 (2014) #294739] are corrected. † 2020 Mathematics
{"title":"Notes on several integral inequalities of Hermite–Hadamard type for s-geometrically\u0000convex functions","authors":"Chun-Ying He, Feng Qi (祁锋)","doi":"10.47443/cm.2022.015","DOIUrl":"https://doi.org/10.47443/cm.2022.015","url":null,"abstract":"In this paper, several erroneous results appeared in the papers [T.-Y. Zhang, A.-P. Ji, F. Qi, Abstr. Appl. Anal. 2012 (2012) #560586] and [T.-Y. Zhang, M. Tunc¸, A.-P. Ji, B.-Y. Xi, Abstr. Appl. Anal. 2014 (2014) #294739] are corrected. † 2020 Mathematics","PeriodicalId":48938,"journal":{"name":"Contributions To Discrete Mathematics","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2022-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89255931","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}