{"title":"Embedding Dimensions of Matrices Whose Entries are Indefinite Distances in the Pseudo-Euclidean Space","authors":"","doi":"10.1007/s41980-023-00842-z","DOIUrl":null,"url":null,"abstract":"<h3>Abstract</h3> <p>A finite set of the Euclidean space is called an <em>s</em>-distance set provided that the number of Euclidean distances in the set is <em>s</em>. Determining the largest possible <em>s</em>-distance set for the Euclidean space of a given dimension is challenging. This problem was solved only when dealing with small values of <em>s</em> and dimensions. Lisoněk (J Combin Theory Ser A 77(2):318–338, 1997) achieved the classification of the largest 2-distance sets for dimensions up to 7, using computer assistance and graph representation theory. In this study, we consider a theory analogous to these results of Lisoněk for the pseudo-Euclidean space <span> <span>\\(\\mathbb {R}^{p,q}\\)</span> </span>. We consider an <em>s</em>-indefinite-distance set in a pseudo-Euclidean space that uses the value <span> <span>$$\\begin{aligned} || \\varvec{x}-\\varvec{y}||&=(x_1-y_1)^2 +\\cdots +(x_p -y_p)^2 \\\\&\\quad -(x_{p+1}-y_{p+1})^2-\\cdots -(x_{p+q}-y_{p+q})^2 \\end{aligned}$$</span> </span>instead of the Euclidean distance. We develop a representation theory for symmetric matrices in the context of <em>s</em>-indefinite-distance sets, which includes or improves the results of Euclidean <em>s</em>-distance sets with large <em>s</em> values. Moreover, we classify the largest possible 2-indefinite-distance sets for small dimensions.</p>","PeriodicalId":9395,"journal":{"name":"Bulletin of The Iranian Mathematical Society","volume":"1 1","pages":""},"PeriodicalIF":0.7000,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Bulletin of The Iranian Mathematical Society","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1007/s41980-023-00842-z","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
A finite set of the Euclidean space is called an s-distance set provided that the number of Euclidean distances in the set is s. Determining the largest possible s-distance set for the Euclidean space of a given dimension is challenging. This problem was solved only when dealing with small values of s and dimensions. Lisoněk (J Combin Theory Ser A 77(2):318–338, 1997) achieved the classification of the largest 2-distance sets for dimensions up to 7, using computer assistance and graph representation theory. In this study, we consider a theory analogous to these results of Lisoněk for the pseudo-Euclidean space \(\mathbb {R}^{p,q}\). We consider an s-indefinite-distance set in a pseudo-Euclidean space that uses the value $$\begin{aligned} || \varvec{x}-\varvec{y}||&=(x_1-y_1)^2 +\cdots +(x_p -y_p)^2 \\&\quad -(x_{p+1}-y_{p+1})^2-\cdots -(x_{p+q}-y_{p+q})^2 \end{aligned}$$instead of the Euclidean distance. We develop a representation theory for symmetric matrices in the context of s-indefinite-distance sets, which includes or improves the results of Euclidean s-distance sets with large s values. Moreover, we classify the largest possible 2-indefinite-distance sets for small dimensions.
期刊介绍:
The Bulletin of the Iranian Mathematical Society (BIMS) publishes original research papers as well as survey articles on a variety of hot topics from distinguished mathematicians. Research papers presented comprise of innovative contributions while expository survey articles feature important results that appeal to a broad audience. Articles are expected to address active research topics and are required to cite existing (including recent) relevant literature appropriately. Papers are critically reviewed on the basis of quality in its exposition, brevity, potential applications, motivation, value and originality of the results. The BIMS takes a high standard policy against any type plagiarism. The editorial board is devoted to solicit expert referees for a fast and unbiased review process.