{"title":"The resultant method in higher dimensions","authors":"N. Harrach , L. Storme , P. Sziklai , M. Takáts","doi":"10.1016/j.ffa.2024.102493","DOIUrl":"10.1016/j.ffa.2024.102493","url":null,"abstract":"<div><p>Stability results play an important role in Galois geometries. The famous resultant method, developed by Szőnyi and Weiner <span><span>[12]</span></span>, <span><span>[11]</span></span>, became very fruitful and resulted in many stability theorems in the last two decades. This method is based on some bivariate polynomials associated to point sets. In this paper we generalize the method for the multidimensional case and show some new applications. We build up the multivariate polynomial machinery and apply it for <em>Rédei polynomials</em>. We can prove a high dimensional analogue of the result of Szőnyi-Weiner <span><span>[9]</span></span>, concerning the number of hyperplanes being skew to a point set of the space. We prove general results on “partial blocking sets”, using the tools we have developed.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"99 ","pages":"Article 102493"},"PeriodicalIF":1.2,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142097573","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":"A note on (2,2)-isogenies via theta coordinates","authors":"Jianming Lin , Saiyu Wang , Chang-An Zhao","doi":"10.1016/j.ffa.2024.102496","DOIUrl":"10.1016/j.ffa.2024.102496","url":null,"abstract":"<div><p>In this paper, we revisit the algorithm for computing chains of <span><math><mo>(</mo><mn>2</mn><mo>,</mo><mn>2</mn><mo>)</mo></math></span>-isogenies between products of elliptic curves via theta coordinates proposed by Dartois et al. For each fundamental block of this algorithm, we provide an explicit inversion-free version. Besides, we exploit the technique of <em>x</em>-only ladder to speed up the computation of gluing isogeny. Finally, we present a mixed optimal strategy, which combines the inversion-elimination tool with the original methods together to execute a chain of <span><math><mo>(</mo><mn>2</mn><mo>,</mo><mn>2</mn><mo>)</mo></math></span>-isogenies.</p><p>We make a cost analysis and present a concrete comparison between ours and the previously known methods for inversion elimination. Furthermore, we implement the mixed optimal strategy for benchmark. The results show that when computing <span><math><mo>(</mo><mn>2</mn><mo>,</mo><mn>2</mn><mo>)</mo></math></span>-isogeny chains with lengths of 126, 208 and 632, compared to Dartois, Maino, Pope and Robert's latest implementation, utilizing our techniques can reduce 9.7%, 9.5% and 9.6% multiplications over the base field <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>, respectively. Therefore, even for the updated version that employs their inversion-free algorithms, our tools still possess an advantage.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"99 ","pages":"Article 102496"},"PeriodicalIF":1.2,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142097567","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":"Achromatic colorings of polarity graphs","authors":"Vladislav Taranchuk , Craig Timmons","doi":"10.1016/j.ffa.2024.102497","DOIUrl":"10.1016/j.ffa.2024.102497","url":null,"abstract":"<div><p>A complete partition of a graph <em>G</em> is a partition of the vertex set such that there is at least one edge between any two parts. The largest <em>r</em> such that <em>G</em> has a complete partition into <em>r</em> parts, each of which is an independent set, is the achromatic number of <em>G</em>. We determine the achromatic number of polarity graphs of biaffine planes coming from generalized polygons. Our colorings of a family of unitary polarity graphs are used to solve a problem of Axenovich and Martin on complete partitions of <span><math><msub><mrow><mi>C</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span>-free graphs. Furthermore, these colorings prove that there are sequences of graphs which are optimally complete and have unbounded degree, a problem that had been studied for the sequence of hypercubes independently by Roichman, and Ahlswede, Bezrukov, Blokhuis, Metsch, and Moorhouse.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"99 ","pages":"Article 102497"},"PeriodicalIF":1.2,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142097574","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 a recent extension of a family of biprojective APN functions","authors":"Lukas Kölsch","doi":"10.1016/j.ffa.2024.102494","DOIUrl":"10.1016/j.ffa.2024.102494","url":null,"abstract":"<div><p>APN functions play a big role as primitives in symmetric cryptography as building blocks that yield optimal resistance to differential attacks. In this note, we consider a recent extension, done by Calderini et al. (2023), of a biprojective APN family introduced by Göloğlu (2022) defined on <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mn>2</mn></mrow><mrow><mn>2</mn><mi>m</mi></mrow></msup></mrow></msub></math></span>. We show that this generalization yields functions equivalent to Göloğlu's original family if <span><math><mn>3</mn><mo>∤</mo><mi>m</mi></math></span>. If <span><math><mn>3</mn><mo>|</mo><mi>m</mi></math></span> we show exactly how many inequivalent APN functions this new family contains. We also show that the family has the minimal image set size for an APN function and determine its Walsh spectrum, hereby settling some open problems. In our proofs, we leverage a group theoretic technique recently developed by Göloğlu and the author in conjunction with a group action on the set of projective polynomials.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"99 ","pages":"Article 102494"},"PeriodicalIF":1.2,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142083363","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":"Four new families of NMDS codes with dimension 4 and their applications","authors":"Yun Ding, Yang Li, Shixin Zhu","doi":"10.1016/j.ffa.2024.102495","DOIUrl":"10.1016/j.ffa.2024.102495","url":null,"abstract":"<div><p>For an <span><math><msub><mrow><mo>[</mo><mi>n</mi><mo>,</mo><mi>k</mi><mo>,</mo><mi>d</mi><mo>]</mo></mrow><mrow><mi>q</mi></mrow></msub></math></span> linear code <span><math><mi>C</mi></math></span>, the singleton defect of <span><math><mi>C</mi></math></span> is defined by <span><math><mi>S</mi><mo>(</mo><mi>C</mi><mo>)</mo><mo>=</mo><mi>n</mi><mo>−</mo><mi>k</mi><mo>+</mo><mn>1</mn><mo>−</mo><mi>d</mi></math></span>. When <span><math><mi>S</mi><mo>(</mo><mi>C</mi><mo>)</mo><mo>=</mo><mi>S</mi><mo>(</mo><msup><mrow><mi>C</mi></mrow><mrow><mo>⊥</mo></mrow></msup><mo>)</mo><mo>=</mo><mn>1</mn></math></span>, the code <span><math><mi>C</mi></math></span> is called a near maximum distance separable (NMDS) code, where <span><math><msup><mrow><mi>C</mi></mrow><mrow><mo>⊥</mo></mrow></msup></math></span> is the dual code of <span><math><mi>C</mi></math></span>. NMDS codes have important applications in finite projective geometries, designs and secret sharing schemes. In this paper, we present four new constructions of infinite families of NMDS codes with dimension 4 and completely determine their weight enumerators. As an application, we also determine the locality of the dual codes of these NMDS codes and obtain four families of distance-optimal and dimension-optimal locally recoverable codes.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"99 ","pages":"Article 102495"},"PeriodicalIF":1.2,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142075831","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}
Maria Montanucci , Guilherme Tizziotti , Giovanni Zini
{"title":"On the automorphism group of a family of maximal curves not covered by the Hermitian curve","authors":"Maria Montanucci , Guilherme Tizziotti , Giovanni Zini","doi":"10.1016/j.ffa.2024.102498","DOIUrl":"10.1016/j.ffa.2024.102498","url":null,"abstract":"<div><p>In this paper we compute the automorphism group of the curves <span><math><msub><mrow><mi>X</mi></mrow><mrow><mi>a</mi><mo>,</mo><mi>b</mi><mo>,</mo><mi>n</mi><mo>,</mo><mi>s</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>Y</mi></mrow><mrow><mi>n</mi><mo>,</mo><mi>s</mi></mrow></msub></math></span> introduced in Tafazolian et al. <span><span>[27]</span></span> as new examples of maximal curves which cannot be covered by the Hermitian curve. They arise as subcovers of the first generalized GK curve (GGS curve). As a result, a new characterization of the GK curve, as a member of this family, is obtained.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"99 ","pages":"Article 102498"},"PeriodicalIF":1.2,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142075829","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":"The subspace structure of maximum cliques in pseudo-Paley graphs from unions of cyclotomic classes","authors":"Shamil Asgarli , Chi Hoi Yip","doi":"10.1016/j.ffa.2024.102492","DOIUrl":"10.1016/j.ffa.2024.102492","url":null,"abstract":"<div><p>Blokhuis showed that all maximum cliques in Paley graphs of square order have a subfield structure. Recently, it has been shown that in Peisert-type graphs, all maximum cliques are affine subspaces, and yet some maximum cliques do not arise from a subfield. In this paper, we investigate the existence of a clique of size <span><math><msqrt><mrow><mi>q</mi></mrow></msqrt></math></span> with a subspace structure in pseudo-Paley graphs of order <em>q</em> from unions of semi-primitive cyclotomic classes. We show that such a clique must have an equal contribution from each cyclotomic class and that most such pseudo-Paley graphs do not admit such cliques, suggesting that the Delsarte bound <span><math><msqrt><mrow><mi>q</mi></mrow></msqrt></math></span> on the clique number can be improved in general. We also prove that generalized Peisert graphs are not isomorphic to Paley graphs or Peisert graphs, confirming a conjecture of Mullin.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"99 ","pages":"Article 102492"},"PeriodicalIF":1.2,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141985199","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}
John Bamberg , Jesse Lansdown , Geertrui Van de Voorde
{"title":"On Bruen chains","authors":"John Bamberg , Jesse Lansdown , Geertrui Van de Voorde","doi":"10.1016/j.ffa.2024.102491","DOIUrl":"10.1016/j.ffa.2024.102491","url":null,"abstract":"<div><p>It is known that a Bruen chain of the three-dimensional projective space <span><math><mrow><mi>PG</mi></mrow><mo>(</mo><mn>3</mn><mo>,</mo><mi>q</mi><mo>)</mo></math></span> exists for every odd prime power <em>q</em> at most 37, except for <span><math><mi>q</mi><mo>=</mo><mn>29</mn></math></span>. It was shown by Cardinali et al. (2005) that Bruen chains do not exist for <span><math><mn>41</mn><mo>⩽</mo><mi>q</mi><mo>⩽</mo><mn>49</mn></math></span>. We develop a model, based on finite fields, which allows us to extend this result to <span><math><mn>41</mn><mo>⩽</mo><mi>q</mi><mo>⩽</mo><mn>97</mn></math></span>, thereby adding more evidence to the conjecture that Bruen chains do not exist for <span><math><mi>q</mi><mo>></mo><mn>37</mn></math></span>. Furthermore, we show that Bruen chains can be realised precisely as the <span><math><mo>(</mo><mi>q</mi><mo>+</mo><mn>1</mn><mo>)</mo><mo>/</mo><mn>2</mn></math></span>-cliques of a two related, yet distinct, undirected simple graphs.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"99 ","pages":"Article 102491"},"PeriodicalIF":1.2,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1071579724001308/pdfft?md5=731484f2ebf31e1586fb859e032c078c&pid=1-s2.0-S1071579724001308-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141985200","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}
Rong Luo , Bingsheng Shen , Yang Yang , Zhengchun Zhou
{"title":"Design of concatenative complete complementary codes for CCC-CDMA via specific sequences and extended Boolean functions","authors":"Rong Luo , Bingsheng Shen , Yang Yang , Zhengchun Zhou","doi":"10.1016/j.ffa.2024.102489","DOIUrl":"10.1016/j.ffa.2024.102489","url":null,"abstract":"<div><p>A complete complementary code (CCC) consists of <em>M</em> sequence sets with size <em>M</em>. The sum of the auto-correlation functions of each sequence set is an impulse function, and the sum of cross-correlation functions of the different sequence sets is equal to zero. Thanks to their excellent correlation, CCCs received extensive use in engineering. In addition, they are strongly connected to orthogonal matrices. In some application scenarios, additional requirements are made for CCCs, such as recently proposed for concatenative CCC (CCCC) division multiple access (CCC-CDMA) technologies. In fact, CCCCs are a special kind of CCCs which requires that each sequence set in CCC be concatenated to form a zero-correlation-zone (ZCZ) sequence set. However, this requirement is challenging, and the literature is thin since there is only one construction in this context. We propose to go beyond the literature through this contribution to reduce the gap between their interest and our limited knowledge of CCCCs. This paper will employ novel methods for designing CCCCs and precisely derive two constructions of these objects. The first is based on perfect cross Z-complementary pair and Hadamard matrices, and the second relies on extended Boolean functions. Specifically, we highlight that optimal and asymptotic optimal CCCCs could be obtained through the proposed constructions. Besides, we shall present a comparison analysis with former structures in the literature and examples to illustrate our main results.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"99 ","pages":"Article 102489"},"PeriodicalIF":1.2,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141978745","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":"Designs with a simple automorphism group","authors":"Alessandro Montinaro , Yanwei Zhao , Zhilin Zhang , Shenglin Zhou","doi":"10.1016/j.ffa.2024.102488","DOIUrl":"10.1016/j.ffa.2024.102488","url":null,"abstract":"<div><p>The classification of the 2-designs with <span><math><mi>λ</mi><mo>=</mo><mn>2</mn></math></span> admitting a flag-transitive automorphism groups with socle <span><math><mi>P</mi><mi>S</mi><mi>L</mi><mo>(</mo><mn>2</mn><mo>,</mo><mi>q</mi><mo>)</mo></math></span> is completed by settling the two open cases in <span><span>[2]</span></span>. The result is achieved by using conics and hyperovals of <span><math><mi>P</mi><mi>G</mi><mo>(</mo><mn>2</mn><mo>,</mo><mi>q</mi><mo>)</mo></math></span>.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"99 ","pages":"Article 102488"},"PeriodicalIF":1.2,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141963503","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}