{"title":"Neighborhood of vertices in the isogeny graph of principally polarized superspecial abelian surfaces","authors":"Zheng Xu , Yi Ouyang , Zijian Zhou","doi":"10.1016/j.ffa.2025.102579","DOIUrl":"10.1016/j.ffa.2025.102579","url":null,"abstract":"<div><div>For two supersingular elliptic curves <em>E</em> and <span><math><msup><mrow><mi>E</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span> defined over <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>p</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></msub></math></span>, let <span><math><mo>[</mo><mi>E</mi><mo>×</mo><msup><mrow><mi>E</mi></mrow><mrow><mo>′</mo></mrow></msup><mo>]</mo></math></span> be the superspecial abelian surface with the principal polarization <span><math><mo>{</mo><mn>0</mn><mo>}</mo><mo>×</mo><msup><mrow><mi>E</mi></mrow><mrow><mo>′</mo></mrow></msup><mo>+</mo><mi>E</mi><mo>×</mo><mo>{</mo><mn>0</mn><mo>}</mo></math></span>. We determine local structure of the vertices <span><math><mo>[</mo><mi>E</mi><mo>×</mo><msup><mrow><mi>E</mi></mrow><mrow><mo>′</mo></mrow></msup><mo>]</mo></math></span> in the <span><math><mo>(</mo><mi>ℓ</mi><mo>,</mo><mi>ℓ</mi><mo>)</mo></math></span>-isogeny graph of principally polarized superspecial abelian surfaces where either <em>E</em> or <span><math><msup><mrow><mi>E</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span> is defined over <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>. We also present a simple new proof of the main theorem in <span><span>[26]</span></span>.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"103 ","pages":"Article 102579"},"PeriodicalIF":1.2,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143139996","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 Gross-Koblitz formula and almost circulant matrices related to Jacobi sums","authors":"Hai-Liang Wu , Li-Yuan Wang","doi":"10.1016/j.ffa.2025.102581","DOIUrl":"10.1016/j.ffa.2025.102581","url":null,"abstract":"<div><div>In this paper, we mainly consider arithmetic properties of the cyclotomic matrix <span><math><msub><mrow><mi>B</mi></mrow><mrow><mi>p</mi></mrow></msub><mo>(</mo><mi>k</mi><mo>)</mo><mo>=</mo><msub><mrow><mo>[</mo><msub><mrow><mi>J</mi></mrow><mrow><mi>p</mi></mrow></msub><msup><mrow><mo>(</mo><msup><mrow><mi>χ</mi></mrow><mrow><mi>k</mi><mi>i</mi></mrow></msup><mo>,</mo><msup><mrow><mi>χ</mi></mrow><mrow><mi>k</mi><mi>j</mi></mrow></msup><mo>)</mo></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup><mo>]</mo></mrow><mrow><mn>1</mn><mo>≤</mo><mi>i</mi><mo>,</mo><mi>j</mi><mo>≤</mo><mo>(</mo><mi>p</mi><mo>−</mo><mn>1</mn><mo>−</mo><mi>k</mi><mo>)</mo><mo>/</mo><mi>k</mi></mrow></msub></math></span>, where <em>p</em> is an odd prime, <span><math><mn>1</mn><mo>≤</mo><mi>k</mi><mo><</mo><mi>p</mi><mo>−</mo><mn>1</mn></math></span> is a divisor of <span><math><mi>p</mi><mo>−</mo><mn>1</mn></math></span>, <em>χ</em> is a generator of the group of all multiplicative characters of the finite field <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>J</mi></mrow><mrow><mi>p</mi></mrow></msub><mo>(</mo><msup><mrow><mi>χ</mi></mrow><mrow><mi>k</mi><mi>i</mi></mrow></msup><mo>,</mo><msup><mrow><mi>χ</mi></mrow><mrow><mi>k</mi><mi>j</mi></mrow></msup><mo>)</mo></math></span> is Jacobi sum over <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>. By using the Gross-Koblitz formula and some <em>p</em>-adic tools, we first prove that<span><span><span><math><msup><mrow><mi>p</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>2</mn></mrow></msup><mi>det</mi><mo></mo><msub><mrow><mi>B</mi></mrow><mrow><mi>p</mi></mrow></msub><mo>(</mo><mi>k</mi><mo>)</mo><mo>≡</mo><msup><mrow><mo>(</mo><mo>−</mo><mn>1</mn><mo>)</mo></mrow><mrow><mfrac><mrow><mo>(</mo><mi>n</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>(</mo><mi>p</mi><mo>+</mo><mi>n</mi><mo>−</mo><mn>3</mn><mo>)</mo></mrow><mrow><mn>2</mn></mrow></mfrac></mrow></msup><msup><mrow><mo>(</mo><mfrac><mrow><mn>1</mn></mrow><mrow><mi>k</mi><mo>!</mo></mrow></mfrac><mo>)</mo></mrow><mrow><mi>n</mi><mo>−</mo><mn>2</mn></mrow></msup><mfrac><mrow><mn>1</mn></mrow><mrow><mo>(</mo><mn>2</mn><mi>k</mi><mo>)</mo><mo>!</mo></mrow></mfrac><mspace></mspace><mo>(</mo><mrow><mi>mod</mi></mrow><mspace></mspace><mi>p</mi><mo>)</mo><mo>,</mo></math></span></span></span> where <span><math><mi>p</mi><mo>−</mo><mn>1</mn><mo>=</mo><mi>k</mi><mi>n</mi></math></span>. By establishing some theories on almost circulant matrices, we show that<span><span><span><math><mi>det</mi><mo></mo><msub><mrow><mi>B</mi></mrow><mrow><mi>p</mi></mrow></msub><mo>(</mo><mi>k</mi><mo>)</mo><mo>=</mo><msup><mrow><mo>(</mo><mo>−</mo><mn>1</mn><mo>)</mo></mrow><mrow><mfrac><mrow><mo>(</mo><mi>n</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>(</mo><mi>p</mi><mo>+</mo><mi>n</mi><mo>−</mo><mn>1</mn><mo>)</mo></mrow><mrow><mn>2</mn></mrow></mfrac></mrow></msup><msup><mrow><mi>p</mi></mro","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"103 ","pages":"Article 102581"},"PeriodicalIF":1.2,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143139256","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}
Mu Yuan , Longjiang Qu , Kangquan Li , Xiaoqiang Wang
{"title":"Implicit functions over finite fields and their applications to good cryptographic functions and linear codes","authors":"Mu Yuan , Longjiang Qu , Kangquan Li , Xiaoqiang Wang","doi":"10.1016/j.ffa.2025.102573","DOIUrl":"10.1016/j.ffa.2025.102573","url":null,"abstract":"<div><div>The implicit function theory has many applications in continuous functions as a powerful tool. This paper initiates the research on handling functions over finite fields with characteristic even from an implicit viewpoint, and exploring the applications of implicit functions in cryptographic functions and linear error-correcting codes. The implicit function <span><math><mmultiscripts><mrow><mi>G</mi></mrow><mprescripts></mprescripts><none></none><mrow><mi>S</mi></mrow></mmultiscripts></math></span> over finite fields is defined by the zeros of a bivariate polynomial <span><math><mi>G</mi><mo>(</mo><mi>X</mi><mo>,</mo><mi>Y</mi><mo>)</mo></math></span>. First, we provide basic concepts and constructions of implicit functions. Second, some strong cryptographic functions are constructed by implicit expressions, including semi-bent (or near-bent) balanced Boolean functions and 4-differentially uniform involution without fixed points. Moreover, we construct some optimal linear codes and minimal codes by using constructed implicitly defined functions. In our proof, some algebra and algebraic curve techniques over finite fields are used. Finally, some problems for future work are provided.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"103 ","pages":"Article 102573"},"PeriodicalIF":1.2,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143139999","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 functions which are CCZ-equivalent but not EA-equivalent to quadratic functions over Fpn","authors":"Jaeseong Jeong , Namhun Koo , Soonhak Kwon","doi":"10.1016/j.ffa.2025.102574","DOIUrl":"10.1016/j.ffa.2025.102574","url":null,"abstract":"<div><div>For a given function <em>F</em> from <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>p</mi></mrow><mrow><mi>n</mi></mrow></msup></mrow></msub></math></span> to itself, determining whether there exists a function which is CCZ-equivalent but EA-inequivalent to <em>F</em> is a very important and interesting problem. For example, Kölsch <span><span>[33]</span></span> showed that there is no function which is CCZ-equivalent but EA-inequivalent to the inverse function. On the other hand, for the cases of Gold function <span><math><mi>F</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>=</mo><msup><mrow><mi>x</mi></mrow><mrow><msup><mrow><mn>2</mn></mrow><mrow><mi>i</mi></mrow></msup><mo>+</mo><mn>1</mn></mrow></msup></math></span> and <span><math><mi>F</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>=</mo><msup><mrow><mi>x</mi></mrow><mrow><mn>3</mn></mrow></msup><mo>+</mo><mrow><mi>Tr</mi></mrow><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mn>9</mn></mrow></msup><mo>)</mo></math></span> over <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mn>2</mn></mrow><mrow><mi>n</mi></mrow></msup></mrow></msub></math></span>, Budaghyan, Carlet and Pott (respectively, Budaghyan, Carlet and Leander) <span><span>[12]</span></span>, <span><span>[14]</span></span> found functions which are CCZ-equivalent but EA-inequivalent to <em>F</em>. In this paper, when a given function <em>F</em> has a component function which has a linear structure, we present functions which are CCZ-equivalent to <em>F</em>, and if suitable conditions are satisfied, the constructed functions are shown to be EA-inequivalent to <em>F</em>. As a consequence, for every quadratic function <em>F</em> on <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mn>2</mn></mrow><mrow><mi>n</mi></mrow></msup></mrow></msub></math></span> (<span><math><mi>n</mi><mo>≥</mo><mn>4</mn></math></span>) with nonlinearity greater than 0 and differential uniformity not exceeding <span><math><msup><mrow><mn>2</mn></mrow><mrow><mi>n</mi><mo>−</mo><mn>3</mn></mrow></msup></math></span>, we explicitly construct functions which are CCZ-equivalent but EA-inequivalent to <em>F</em>. Also for every non-planar quadratic function on <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>p</mi></mrow><mrow><mi>n</mi></mrow></msup></mrow></msub></math></span> <span><math><mo>(</mo><mi>p</mi><mo>></mo><mn>2</mn><mo>,</mo><mi>n</mi><mo>≥</mo><mn>4</mn><mo>)</mo></math></span> with <span><math><mo>|</mo><msub><mrow><mi>W</mi></mrow><mrow><mi>F</mi></mrow></msub><mo>|</mo><mo>≤</mo><msup><mrow><mi>p</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msup></math></span> and differential uniformity not exceeding <span><math><msup><mrow><mi>p</mi></mrow><mrow><mi>n</mi><mo>−</mo><mn>3</mn></mrow></msup></math></span>, we explicitly construct functions which are CCZ-equivalent but EA-inequivalent to <em>F</em>. As an application, for a proper divisor <em>m</em> of <em>n</em>, we present many examples","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"103 ","pages":"Article 102574"},"PeriodicalIF":1.2,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143139997","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 p-rank of singular curves and their smooth models","authors":"Sadık Terzi","doi":"10.1016/j.ffa.2025.102578","DOIUrl":"10.1016/j.ffa.2025.102578","url":null,"abstract":"<div><div>In this paper, we are concerned with the computation of the <em>p</em>-rank and <em>a</em>-number of singular curves and their smooth models. We consider a pair <span><math><mi>X</mi><mo>,</mo><msup><mrow><mi>X</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span> of proper curves over an algebraically closed field <em>k</em> of characteristic <em>p</em>, where <span><math><msup><mrow><mi>X</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span> is a singular curve which lies on a smooth projective variety, particularly on smooth projective surfaces <em>S</em> (with <span><math><msub><mrow><mi>p</mi></mrow><mrow><mi>g</mi></mrow></msub><mo>(</mo><mi>S</mi><mo>)</mo><mo>=</mo><mn>0</mn><mo>=</mo><mi>q</mi><mo>(</mo><mi>S</mi><mo>)</mo></math></span>) and <em>X</em> is the smooth model of <span><math><msup><mrow><mi>X</mi></mrow><mrow><mo>′</mo></mrow></msup></math></span>. We determine the <em>p</em>-rank of <em>X</em> by using the exact sequence of group schemes relating the Jacobians <span><math><msub><mrow><mi>J</mi></mrow><mrow><mi>X</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>J</mi></mrow><mrow><msup><mrow><mi>X</mi></mrow><mrow><mo>′</mo></mrow></msup></mrow></msub></math></span>. As an application, we determine a relation about the fundamental invariants <em>p</em>-rank and <em>a</em>-number of a family of singular curves and their smooth models. Moreover, we calculate <em>a</em>-number and find lower bound for <em>p</em>-rank of a family of smooth curves.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"103 ","pages":"Article 102578"},"PeriodicalIF":1.2,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140004","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}
Daniele Bartoli , Francesco Ghiandoni , Alessandro Giannoni , Giuseppe Marino
{"title":"A new family of 2-scattered subspaces and related MRD codes","authors":"Daniele Bartoli , Francesco Ghiandoni , Alessandro Giannoni , Giuseppe Marino","doi":"10.1016/j.ffa.2025.102572","DOIUrl":"10.1016/j.ffa.2025.102572","url":null,"abstract":"<div><div>Scattered subspaces and <em>h</em>-scattered subspaces have been extensively studied in recent decades for both theoretical purposes and their connections to various applications. While numerous constructions of scattered subspaces exist, relatively few are known about <em>h</em>-scattered subspaces with <span><math><mi>h</mi><mo>≥</mo><mn>2</mn></math></span>. In this paper, we establish the existence of maximum 2-scattered <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span>-subspaces in <span><math><mi>V</mi><mo>(</mo><mi>r</mi><mo>,</mo><msup><mrow><mi>q</mi></mrow><mrow><mn>6</mn></mrow></msup><mo>)</mo></math></span> whenever <span><math><mi>r</mi><mo>≥</mo><mn>3</mn></math></span>, <span><math><mi>r</mi><mo>≠</mo><mn>5</mn></math></span>, and <em>q</em> is an odd power of 2. Additionally, we explore the corresponding MRD codes.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"103 ","pages":"Article 102572"},"PeriodicalIF":1.2,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140002","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":"On the distribution of quadratic residues","authors":"I.D. Shkredov","doi":"10.1016/j.ffa.2025.102577","DOIUrl":"10.1016/j.ffa.2025.102577","url":null,"abstract":"<div><div>In our paper, we apply additive–combinatorial methods to study the distribution of the set of squares <span><math><mi>R</mi></math></span> in the prime field. We obtain the best upper bound on the number of gaps in <span><math><mi>R</mi></math></span> at the moment and generalize this result for sets with small doubling.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"103 ","pages":"Article 102577"},"PeriodicalIF":1.2,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143139255","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":"Regular sets of lines in rank 3 polar spaces","authors":"Ferdinand Ihringer , Morgan Rodgers","doi":"10.1016/j.ffa.2024.102569","DOIUrl":"10.1016/j.ffa.2024.102569","url":null,"abstract":"<div><div>There are 6 families of finite polar spaces of rank 3. The set of lines in a rank 3 polar space forms a rank 5 association scheme. We determine the regular sets of minimal size in several of these polar spaces, and describe some interesting examples. We also give a new family of Cameron–Liebler sets of generators in the polar spaces <span><math><msup><mrow><mi>O</mi></mrow><mrow><mo>+</mo></mrow></msup><mo>(</mo><mn>10</mn><mo>,</mo><mi>q</mi><mo>)</mo></math></span> when <span><math><mi>q</mi><mo>=</mo><msup><mrow><mn>3</mn></mrow><mrow><mi>h</mi></mrow></msup></math></span> using a regular set of lines in <span><math><mi>O</mi><mo>(</mo><mn>7</mn><mo>,</mo><mi>q</mi><mo>)</mo></math></span>.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"103 ","pages":"Article 102569"},"PeriodicalIF":1.2,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140003","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":"Small solutions of generic ternary quadratic congruences to general moduli","authors":"Stephan Baier, Aishik Chattopadhyay","doi":"10.1016/j.ffa.2025.102571","DOIUrl":"10.1016/j.ffa.2025.102571","url":null,"abstract":"<div><div>We study small non-trivial solutions of quadratic congruences of the form <span><math><msubsup><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></msubsup><mo>+</mo><msub><mrow><mi>α</mi></mrow><mrow><mn>2</mn></mrow></msub><msubsup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow><mrow><mn>2</mn></mrow></msubsup><mo>+</mo><msub><mrow><mi>α</mi></mrow><mrow><mn>3</mn></mrow></msub><msubsup><mrow><mi>x</mi></mrow><mrow><mn>3</mn></mrow><mrow><mn>2</mn></mrow></msubsup><mo>≡</mo><mn>0</mn><mspace></mspace><mrow><mi>mod</mi></mrow><mspace></mspace><mi>q</mi></math></span>, with <em>q</em> being an odd natural number, in an average sense. This extends previous work of the authors in which they considered the case of prime power moduli <em>q</em>. Above, <span><math><msub><mrow><mi>α</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> is arbitrary but fixed and <span><math><msub><mrow><mi>α</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span> is variable, and we assume that <span><math><mo>(</mo><msub><mrow><mi>α</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>α</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>,</mo><mi>q</mi><mo>)</mo><mo>=</mo><mn>1</mn></math></span>. We show that for all <span><math><msub><mrow><mi>α</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span> modulo <em>q</em> which are coprime to <em>q</em> except for a small number of <span><math><msub><mrow><mi>α</mi></mrow><mrow><mn>3</mn></mrow></msub></math></span>'s, an asymptotic formula for the number of solutions <span><math><mo>(</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>,</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>)</mo></math></span> to the congruence <span><math><msubsup><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow><mrow><mn>2</mn></mrow></msubsup><mo>+</mo><msub><mrow><mi>α</mi></mrow><mrow><mn>2</mn></mrow></msub><msubsup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow><mrow><mn>2</mn></mrow></msubsup><mo>+</mo><msub><mrow><mi>α</mi></mrow><mrow><mn>3</mn></mrow></msub><msubsup><mrow><mi>x</mi></mrow><mrow><mn>3</mn></mrow><mrow><mn>2</mn></mrow></msubsup><mo>≡</mo><mn>0</mn><mspace></mspace><mrow><mi>mod</mi></mrow><mspace></mspace><mi>q</mi></math></span> with <span><math><mi>max</mi><mo></mo><mo>{</mo><mo>|</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>|</mo><mo>,</mo><mo>|</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>|</mo><mo>,</mo><mo>|</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>|</mo><mo>}</mo><mo>≤</mo><mi>N</mi></math></span> and <span><math><mo>(</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>,</mo><mi>q</mi><mo>)</mo><mo>=</mo><mn>1</mn></math></span> holds if <span><math><mi>N</mi><mo>≥</mo><msup><mrow><mi>q</mi></mrow><mrow><mn>11</mn><mo>/</mo><mn>24</mn><mo>+</mo><mi>ε</mi></mrow></msup></math></span> and <em>q</em>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"103 ","pages":"Article 102571"},"PeriodicalIF":1.2,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140006","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":"(2p + 1)-class association schemes from the generalized Maiorana-McFarland class","authors":"Nurdagül Anbar , Tekgül Kalaycı , Wilfried Meidl , Ferruh Özbudak","doi":"10.1016/j.ffa.2024.102568","DOIUrl":"10.1016/j.ffa.2024.102568","url":null,"abstract":"<div><div>In several articles, it has been shown that the preimage set partition of weakly regular (vectorial) bent functions, which are vectorial dual-bent, give rise to association schemes. The first construction of association schemes from certain partitions obtained from non-weakly regular bent functions, namely from ternary generalized Maiorana-McFarland functions, is presented in Özbudak and Pelen (2022) <span><span>[32]</span></span>.</div><div>In this article, association schemes are obtained from generalized Maiorana-McFarland bent functions from <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>p</mi></mrow><mrow><mi>n</mi></mrow></msup></mrow></msub><mo>×</mo><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>p</mi></mrow><mrow><mi>k</mi></mrow></msup></mrow></msub><mo>×</mo><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>p</mi></mrow><mrow><mi>k</mi></mrow></msup></mrow></msub></math></span> to <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>, which are constructed from <span><math><msup><mrow><mi>p</mi></mrow><mrow><mi>k</mi></mrow></msup></math></span> bent functions from <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>p</mi></mrow><mrow><mi>n</mi></mrow></msup></mrow></msub></math></span> to <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> with certain properties. The obtained schemes are in general <span><math><mo>(</mo><mn>2</mn><mi>p</mi><mo>+</mo><mn>1</mn><mo>)</mo></math></span>-class association schemes. In the case that <span><math><mi>n</mi><mo>=</mo><mn>1</mn></math></span> respectively in one case for <span><math><mi>n</mi><mo>=</mo><mn>2</mn></math></span>, the association schemes reduce to <span><math><mo>(</mo><mn>3</mn><mi>p</mi><mo>+</mo><mn>1</mn><mo>)</mo><mo>/</mo><mn>2</mn></math></span>-class association schemes respectively to 2<em>p</em>-class association schemes. For <span><math><mi>p</mi><mo>=</mo><mn>3</mn></math></span>, these schemes are the 5-class and 6-class association schemes obtained by Özbudak and Pelen. Therefore, the construction in this article substantially generalizes these earlier constructions. Also note that for <span><math><mi>n</mi><mo>=</mo><mn>1</mn></math></span> respectively <span><math><mi>n</mi><mo>=</mo><mn>2</mn></math></span>, the construction is based in bent functions from <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> to <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> respectively from <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>p</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></msub></math></span> to <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>, for which the choices are very limited.</div><div>Depending on the choice of the bent functions used for the construction, the resulting generalized Maiorana-McFarland function may be weakly reg","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"103 ","pages":"Article 102568"},"PeriodicalIF":1.2,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143140007","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}