{"title":"Self-dual 2-quasi negacyclic codes over finite fields","authors":"Yun Fan, Yue Leng","doi":"10.1016/j.ffa.2024.102541","DOIUrl":"10.1016/j.ffa.2024.102541","url":null,"abstract":"<div><div>In this paper, we investigate the existence and asymptotic properties of self-dual 2-quasi negacyclic codes of length 2<em>n</em> over a finite field of cardinality <em>q</em>. When <em>n</em> is odd, we show that the <em>q</em>-ary self-dual 2-quasi negacyclic codes exist if and only if <span><math><mi>q</mi><mspace></mspace><mo>≢</mo><mo>−</mo><mn>1</mn><mspace></mspace><mo>(</mo><mrow><mi>mod</mi></mrow><mspace></mspace><mn>4</mn><mo>)</mo></math></span>. When <em>n</em> is even, we prove that the <em>q</em>-ary self-dual 2-quasi negacyclic codes always exist. By using the technique introduced in this paper, we prove that <em>q</em>-ary self-dual 2-quasi negacyclic codes are asymptotically good.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"101 ","pages":"Article 102541"},"PeriodicalIF":1.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Intersecting families of polynomials over finite fields","authors":"Nika Salia , Dávid Tóth","doi":"10.1016/j.ffa.2024.102540","DOIUrl":"10.1016/j.ffa.2024.102540","url":null,"abstract":"<div><div>This paper demonstrates an analog of the Erdős–Ko–Rado theorem to polynomial rings over finite fields, affirmatively answering a conjecture of C. Tompkins.</div><div>A <em>k</em>-uniform family of subsets of a set of size <em>n</em> is <em>ℓ</em>-intersecting if any two subsets in the family intersect in at least <em>ℓ</em> elements. The study of such intersecting families is a core subject of extremal set theory, tracing its roots to the seminal 1961 Erdős–Ko–Rado theorem, which establishes a sharp upper bound on the size of these families. Here, we extend the Erdős–Ko–Rado theorem to polynomial rings over finite fields.</div><div>Specifically, we determine the largest possible size of a family of monic polynomials, each of degree <em>n</em>, over a finite field <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span>, where every pair of polynomials in the family shares a common factor of degree at least <em>ℓ</em>. We prove that the upper bound for this size is <span><math><msup><mrow><mi>q</mi></mrow><mrow><mi>n</mi><mo>−</mo><mi>ℓ</mi></mrow></msup></math></span> and characterize all extremal families that achieve this maximum size.</div><div>Extending to triple-intersecting families, where every triplet of polynomials shares a common factor of degree at least <em>ℓ</em>, we prove that only trivial families achieve the corresponding upper bound. Moreover, by relaxing the conditions to include polynomials of degree at most <em>n</em>, we affirm that only trivial families achieve the corresponding upper bound.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"101 ","pages":"Article 102540"},"PeriodicalIF":1.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Partial difference sets with Denniston parameters in elementary abelian p-groups","authors":"Jingjun Bao , Qing Xiang , Meng Zhao","doi":"10.1016/j.ffa.2024.102539","DOIUrl":"10.1016/j.ffa.2024.102539","url":null,"abstract":"<div><div>Denniston <span><span>[12]</span></span> constructed partial difference sets (PDS) with parameters <span><math><mo>(</mo><msup><mrow><mn>2</mn></mrow><mrow><mn>3</mn><mi>m</mi></mrow></msup><mo>,</mo><mo>(</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>m</mi><mo>+</mo><mi>r</mi></mrow></msup><mo>−</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>m</mi></mrow></msup><mo>+</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>r</mi></mrow></msup><mo>)</mo><mo>(</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>m</mi></mrow></msup><mo>−</mo><mn>1</mn><mo>)</mo><mo>,</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>m</mi></mrow></msup><mo>−</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>r</mi></mrow></msup><mo>+</mo><mo>(</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>m</mi><mo>+</mo><mi>r</mi></mrow></msup><mo>−</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>m</mi></mrow></msup><mo>+</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>r</mi></mrow></msup><mo>)</mo><mo>(</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>r</mi></mrow></msup><mo>−</mo><mn>2</mn><mo>)</mo><mo>,</mo><mo>(</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>m</mi><mo>+</mo><mi>r</mi></mrow></msup><mo>−</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>m</mi></mrow></msup><mo>+</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>r</mi></mrow></msup><mo>)</mo><mo>(</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>r</mi></mrow></msup><mo>−</mo><mn>1</mn><mo>)</mo><mo>)</mo></math></span> in elementary abelian groups of order <span><math><msup><mrow><mn>2</mn></mrow><mrow><mn>3</mn><mi>m</mi></mrow></msup></math></span> for all <span><math><mi>m</mi><mo>≥</mo><mn>2</mn></math></span> and <span><math><mn>1</mn><mo>≤</mo><mi>r</mi><mo><</mo><mi>m</mi></math></span>. These PDS arise from maximal arcs in the Desarguesian projective planes PG<span><math><mo>(</mo><mn>2</mn><mo>,</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>m</mi></mrow></msup><mo>)</mo></math></span>. Davis et al. <span><span>[10]</span></span> and also De Winter <span><span>[13]</span></span> presented constructions of PDS with Denniston parameters <span><math><mo>(</mo><msup><mrow><mi>p</mi></mrow><mrow><mn>3</mn><mi>m</mi></mrow></msup><mo>,</mo><mo>(</mo><msup><mrow><mi>p</mi></mrow><mrow><mi>m</mi><mo>+</mo><mi>r</mi></mrow></msup><mo>−</mo><msup><mrow><mi>p</mi></mrow><mrow><mi>m</mi></mrow></msup><mo>+</mo><msup><mrow><mi>p</mi></mrow><mrow><mi>r</mi></mrow></msup><mo>)</mo><mo>(</mo><msup><mrow><mi>p</mi></mrow><mrow><mi>m</mi></mrow></msup><mo>−</mo><mn>1</mn><mo>)</mo><mo>,</mo><msup><mrow><mi>p</mi></mrow><mrow><mi>m</mi></mrow></msup><mo>−</mo><msup><mrow><mi>p</mi></mrow><mrow><mi>r</mi></mrow></msup><mo>+</mo><mo>(</mo><msup><mrow><mi>p</mi></mrow><mrow><mi>m</mi><mo>+</mo><mi>r</mi></mrow></msup><mo>−</mo><msup><mrow><mi>p</mi></mrow><mrow><mi>m</mi></mrow></msup><mo>+</mo><msup><mrow><mi>p</mi></mrow><mrow><mi>r</mi></mrow></msup><mo>)</mo><mo>(</mo><msup><mrow><mi>p</mi></mrow><mrow><mi>r</mi></mrow></msup><mo>−</mo><mn>2</mn><mo>)</mo><mo>,</mo><mo>(</mo><msup><mrow><mi>p</mi>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"101 ","pages":"Article 102539"},"PeriodicalIF":1.2,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142660193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Asymptotic distributions of the number of zeros of random polynomials in Hayes equivalence class over a finite field","authors":"Zhicheng Gao","doi":"10.1016/j.ffa.2024.102524","DOIUrl":"10.1016/j.ffa.2024.102524","url":null,"abstract":"<div><div>Hayes equivalence is defined on monic polynomials over a finite field <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span> in terms of the prescribed leading coefficients and the residue classes modulo a given monic polynomial <em>Q</em>. We study the distribution of the number of zeros in a random polynomial over finite fields in a given Hayes equivalence class. It is well known that the number of distinct zeros of a random polynomial over <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span> is asymptotically Poisson with mean 1. We show that this is also true for random polynomials in any given Hayes equivalence class. Asymptotic formulas are also given for the number of such polynomials when the degree of such polynomials is proportional to <em>q</em> and the degree of <em>Q</em> and the number of prescribed leading coefficients are bounded by <span><math><msqrt><mrow><mi>q</mi></mrow></msqrt></math></span>. When <span><math><mi>Q</mi><mo>=</mo><mn>1</mn></math></span>, the problem is equivalent to the study of the distance distribution in Reed-Solomon codes. Our asymptotic formulas extend some earlier results and imply that all words for a large family of Reed-Solomon codes are ordinary, which further supports the well-known <em>Deep-Hole</em> Conjecture.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"101 ","pages":"Article 102524"},"PeriodicalIF":1.2,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142594089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Quasi-polycyclic and skew quasi-polycyclic codes over Fq","authors":"Tushar Bag, Daniel Panario","doi":"10.1016/j.ffa.2024.102536","DOIUrl":"10.1016/j.ffa.2024.102536","url":null,"abstract":"<div><div>In this research, our focus is on investigating 1-generator right quasi-polycyclic (QPC) codes over fields. We provide a detailed description of how linear codes with substantial minimum distances can be constructed from QPC codes. We analyze dual QPC codes under various inner products and use them to construct quantum error-correcting codes. Furthermore, our research includes a dedicated section that delves into the area of skew quasi-polycyclic (SQPC) codes, investigating their properties and the role of generators in their construction. This section expands our study to encompass the intriguing area of SQPC codes, offering insights into the non-commutative version of QPC codes, their characteristics and generator structures. Our work deals with the structural properties of QPC, skew polycyclic and SQPC codes, shedding light on their potential for enhancing the field of coding theory.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"101 ","pages":"Article 102536"},"PeriodicalIF":1.2,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Self-orthogonal cyclic codes with good parameters","authors":"Jiayuan Zhang, Xiaoshan Kai, Ping Li","doi":"10.1016/j.ffa.2024.102534","DOIUrl":"10.1016/j.ffa.2024.102534","url":null,"abstract":"<div><div>The construction of self-orthogonal codes is an interesting topic due to their wide applications in communication and cryptography. In this paper, we construct several families of self-orthogonal cyclic codes with length <span><math><mi>n</mi><mo>=</mo><mfrac><mrow><msup><mrow><mi>q</mi></mrow><mrow><mi>m</mi></mrow></msup><mo>−</mo><mn>1</mn></mrow><mrow><mi>λ</mi></mrow></mfrac></math></span>, where <span><math><mi>λ</mi><mo>|</mo><mi>q</mi><mo>−</mo><mn>1</mn></math></span> and <span><math><mi>m</mi><mo>≥</mo><mn>3</mn></math></span> is odd. It is proved that there exist <em>q</em>-ary self-orthogonal cyclic codes with parameters <span><math><mo>[</mo><mi>n</mi><mo>,</mo><mfrac><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac><mo>,</mo><mo>≥</mo><mi>d</mi><mo>]</mo></math></span> for even prime power <em>q</em>, and <span><math><mo>[</mo><mi>n</mi><mo>,</mo><mfrac><mrow><mi>n</mi></mrow><mrow><mn>2</mn></mrow></mfrac><mo>−</mo><mn>1</mn><mo>,</mo><mo>≥</mo><mi>d</mi><mo>]</mo></math></span> or <span><math><mo>[</mo><mi>n</mi><mo>,</mo><mfrac><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac><mo>,</mo><mo>≥</mo><mi>d</mi><mo>]</mo></math></span> for odd prime power <em>q</em>, where <em>d</em> is significantly better than the square-root bound. These several families of self-orthogonal cyclic codes contain some optimal linear codes.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"101 ","pages":"Article 102534"},"PeriodicalIF":1.2,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Linear codes from planar functions and related covering codes","authors":"Yanan Wu, Yanbin Pan","doi":"10.1016/j.ffa.2024.102535","DOIUrl":"10.1016/j.ffa.2024.102535","url":null,"abstract":"<div><div>Linear codes with few weights have wide applications in consumer electronics, data storage system and secret sharing. In this paper, by virtue of planar functions, several infinite families of <em>l</em>-weight linear codes over <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> are constructed, where <em>l</em> can be any positive integer and <em>p</em> is a prime number. The weight distributions of these codes are determined completely by utilizing certain approach on exponential sums. Experiments show that some (almost) optimal codes in small dimensions can be produced from our results. Moreover, the related covering codes are also investigated.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"101 ","pages":"Article 102535"},"PeriodicalIF":1.2,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Improvements of the Hasse-Weil-Serre bound over global function fields","authors":"Jinjoo Yoo , Yoonjin Lee","doi":"10.1016/j.ffa.2024.102538","DOIUrl":"10.1016/j.ffa.2024.102538","url":null,"abstract":"<div><div>We improve the Hasse-Weil-Serre bound over a global function field <em>K</em> with relatively large genus in terms of the ramification behavior of the finite places and the infinite places for <span><math><mi>K</mi><mo>/</mo><mi>k</mi></math></span>, where <em>k</em> is the rational function field <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub><mo>(</mo><mi>T</mi><mo>)</mo></math></span>. Furthermore, we improve the Hasse-Weil-Serre bound over a global function field <em>K</em> in terms of the defining equation of <em>K</em>. As an application of our main result, we apply our bound to some well-known extensions: <em>Kummer extensions</em> and <em>elementary abelian p-extensions</em>, where <em>p</em> is the characteristic of <em>k</em>. In fact, elementary abelian <em>p</em>-extensions include <em>Artin-Schreier type extensions</em>, <em>Artin-Schreier extensions</em>, and <em>Suzuki function fields</em>. Moreover, we present infinite families of global function fields for Kummer extensions, Artin-Schreier type extensions, and elementary abelian <em>p</em>-extensions but not Artin-Schreier type extensions, which meet our improved bound: our bound is a sharp bound in these families. We also compare our new bound with some known data given in <span><span>manypoints.org</span><svg><path></path></svg></span>, which is the database on the rational points of algebraic curves. This comparison shows a meaningful improvement of our results on the bound of the number of the rational places of <em>K</em>.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"101 ","pages":"Article 102538"},"PeriodicalIF":1.2,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"On the cyclotomic field Q(e2πi/p) and Zhi-Wei Sun's conjecture on det Mp","authors":"Li-Yuan Wang , Hai-Liang Wu","doi":"10.1016/j.ffa.2024.102533","DOIUrl":"10.1016/j.ffa.2024.102533","url":null,"abstract":"<div><div>In 2019, Zhi-Wei Sun posed an interesting conjecture on certain determinants with Legendre symbol entries. In this paper, by using the arithmetic properties of <em>p</em>-th cyclotomic field and the finite field <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>, we confirm this conjecture.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"101 ","pages":"Article 102533"},"PeriodicalIF":1.2,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Optimal quinary cyclic codes with three zeros","authors":"Jinmei Fan , Xiangyong Zeng","doi":"10.1016/j.ffa.2024.102537","DOIUrl":"10.1016/j.ffa.2024.102537","url":null,"abstract":"<div><div>Optimal cyclic codes have received a lot of attention and much progress has been made. However, little is known about optimal quinary cyclic codes. In this paper, by analyzing irreducible factors of certain polynomials over finite fields and utilizing multivariate method, three classes of optimal quinary cyclic codes with parameters <span><math><mo>[</mo><msup><mrow><mn>5</mn></mrow><mrow><mi>m</mi></mrow></msup><mo>−</mo><mn>1</mn><mo>,</mo><msup><mrow><mn>5</mn></mrow><mrow><mi>m</mi></mrow></msup><mo>−</mo><mn>2</mn><mi>m</mi><mo>−</mo><mn>2</mn><mo>,</mo><mn>4</mn><mo>]</mo></math></span> and three zeros are presented.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"101 ","pages":"Article 102537"},"PeriodicalIF":1.2,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}