{"title":"On the equivalence of certain quasi-Hermitian varieties","authors":"Angela Aguglia, Luca Giuzzi","doi":"10.1002/jcd.21870","DOIUrl":null,"url":null,"abstract":"<p>By Aguglia et al., new quasi-Hermitian varieties <math>\n <semantics>\n <mrow>\n <msub>\n <mi>ℳ</mi>\n <mrow>\n <mi>α</mi>\n <mo>,</mo>\n <mi>β</mi>\n </mrow>\n </msub>\n </mrow>\n <annotation> ${{\\rm{ {\\mathcal M} }}}_{\\alpha ,\\beta }$</annotation>\n </semantics></math> in <math>\n <semantics>\n <mrow>\n <mtext>PG</mtext>\n <mrow>\n <mo>(</mo>\n <mrow>\n <mi>r</mi>\n <mo>,</mo>\n <msup>\n <mi>q</mi>\n <mn>2</mn>\n </msup>\n </mrow>\n <mo>)</mo>\n </mrow>\n </mrow>\n <annotation> $\\text{PG}(r,{q}^{2})$</annotation>\n </semantics></math> depending on a pair of parameters <math>\n <semantics>\n <mrow>\n <mi>α</mi>\n <mo>,</mo>\n <mi>β</mi>\n </mrow>\n <annotation> $\\alpha ,\\beta $</annotation>\n </semantics></math> from the underlying field <math>\n <semantics>\n <mrow>\n <mtext>GF</mtext>\n <mrow>\n <mo>(</mo>\n <msup>\n <mi>q</mi>\n <mn>2</mn>\n </msup>\n <mo>)</mo>\n </mrow>\n </mrow>\n <annotation> $\\text{GF}({q}^{2})$</annotation>\n </semantics></math> have been constructed. In the present paper we study the structure of the lines contained in <math>\n <semantics>\n <mrow>\n <msub>\n <mi>ℳ</mi>\n <mrow>\n <mi>α</mi>\n <mo>,</mo>\n <mi>β</mi>\n </mrow>\n </msub>\n </mrow>\n <annotation> ${{\\rm{ {\\mathcal M} }}}_{\\alpha ,\\beta }$</annotation>\n </semantics></math> and consequently determine the projective equivalence classes of such varieties for <math>\n <semantics>\n <mrow>\n <mi>q</mi>\n </mrow>\n <annotation> $q$</annotation>\n </semantics></math> odd and <math>\n <semantics>\n <mrow>\n <mi>r</mi>\n <mo>=</mo>\n <mn>3</mn>\n </mrow>\n <annotation> $r=3$</annotation>\n </semantics></math>. As a byproduct, we also prove that the collinearity graph of <math>\n <semantics>\n <mrow>\n <msub>\n <mi>ℳ</mi>\n <mrow>\n <mi>α</mi>\n <mo>,</mo>\n <mi>β</mi>\n </mrow>\n </msub>\n </mrow>\n <annotation> ${{\\rm{ {\\mathcal M} }}}_{\\alpha ,\\beta }$</annotation>\n </semantics></math> is connected with diameter 3 for <math>\n <semantics>\n <mrow>\n <mi>q</mi>\n <mo>≡</mo>\n <mn>1</mn>\n <mspace></mspace>\n <mrow>\n <mo>(</mo>\n <mrow>\n <mi>mod</mi>\n <mspace></mspace>\n <mn>4</mn>\n </mrow>\n <mo>)</mo>\n </mrow>\n </mrow>\n <annotation> $q\\equiv 1\\,(\\mathrm{mod}\\,4)$</annotation>\n </semantics></math>.</p>","PeriodicalId":15389,"journal":{"name":"Journal of Combinatorial Designs","volume":"31 2","pages":"124-138"},"PeriodicalIF":0.5000,"publicationDate":"2022-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"3","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Combinatorial Designs","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/jcd.21870","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 3
Abstract
By Aguglia et al., new quasi-Hermitian varieties in depending on a pair of parameters from the underlying field have been constructed. In the present paper we study the structure of the lines contained in and consequently determine the projective equivalence classes of such varieties for odd and . As a byproduct, we also prove that the collinearity graph of is connected with diameter 3 for .
期刊介绍:
The Journal of Combinatorial Designs is an international journal devoted to the timely publication of the most influential papers in the area of combinatorial design theory. All topics in design theory, and in which design theory has important applications, are covered, including:
block designs, t-designs, pairwise balanced designs and group divisible designs
Latin squares, quasigroups, and related algebras
computational methods in design theory
construction methods
applications in computer science, experimental design theory, and coding theory
graph decompositions, factorizations, and design-theoretic techniques in graph theory and extremal combinatorics
finite geometry and its relation with design theory.
algebraic aspects of design theory.
Researchers and scientists can depend on the Journal of Combinatorial Designs for the most recent developments in this rapidly growing field, and to provide a forum for both theoretical research and applications. All papers appearing in the Journal of Combinatorial Designs are carefully peer refereed.