Pub Date : 2024-07-31DOI: 10.1016/j.ffa.2024.102478
Yuqing Fu , Hongwei Liu
BCH codes form a special subclass of cyclic codes and have been extensively studied in the past decades. Determining the parameters of BCH codes, however, has been an important but difficult problem. Recently, in order to further investigate the dual codes of BCH codes, the concept of dually-BCH codes was proposed. In this paper, we study BCH codes of lengths and over the finite field , both of which are LCD codes. The dimensions of narrow-sense BCH codes of length with designed distance are determined, where and . Lower bounds on the minimum distances of the dual codes of narrow-sense BCH codes of length are developed for odd q, which are good in some cases. Moreover, sufficient and necessary conditions for the even-like subcodes of narrow-sense BCH codes of length being dually-BCH codes are presented, where q is odd and .
{"title":"Two classes of LCD BCH codes over finite fields","authors":"Yuqing Fu , Hongwei Liu","doi":"10.1016/j.ffa.2024.102478","DOIUrl":"10.1016/j.ffa.2024.102478","url":null,"abstract":"<div><p>BCH codes form a special subclass of cyclic codes and have been extensively studied in the past decades. Determining the parameters of BCH codes, however, has been an important but difficult problem. Recently, in order to further investigate the dual codes of BCH codes, the concept of dually-BCH codes was proposed. In this paper, we study BCH codes of lengths <span><math><mfrac><mrow><msup><mrow><mi>q</mi></mrow><mrow><mi>m</mi></mrow></msup><mo>+</mo><mn>1</mn></mrow><mrow><mi>q</mi><mo>+</mo><mn>1</mn></mrow></mfrac></math></span> and <span><math><msup><mrow><mi>q</mi></mrow><mrow><mi>m</mi></mrow></msup><mo>+</mo><mn>1</mn></math></span> over the finite field <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span>, both of which are LCD codes. The dimensions of narrow-sense BCH codes of length <span><math><mfrac><mrow><msup><mrow><mi>q</mi></mrow><mrow><mi>m</mi></mrow></msup><mo>+</mo><mn>1</mn></mrow><mrow><mi>q</mi><mo>+</mo><mn>1</mn></mrow></mfrac></math></span> with designed distance <span><math><mi>δ</mi><mo>=</mo><mi>ℓ</mi><msup><mrow><mi>q</mi></mrow><mrow><mfrac><mrow><mi>m</mi><mo>−</mo><mn>1</mn></mrow><mrow><mn>2</mn></mrow></mfrac></mrow></msup><mo>+</mo><mn>1</mn></math></span> are determined, where <span><math><mi>q</mi><mo>></mo><mn>2</mn></math></span> and <span><math><mn>2</mn><mo>≤</mo><mi>ℓ</mi><mo>≤</mo><mi>q</mi><mo>−</mo><mn>1</mn></math></span>. Lower bounds on the minimum distances of the dual codes of narrow-sense BCH codes of length <span><math><msup><mrow><mi>q</mi></mrow><mrow><mi>m</mi></mrow></msup><mo>+</mo><mn>1</mn></math></span> are developed for odd <em>q</em>, which are good in some cases. Moreover, sufficient and necessary conditions for the even-like subcodes of narrow-sense BCH codes of length <span><math><msup><mrow><mi>q</mi></mrow><mrow><mi>m</mi></mrow></msup><mo>+</mo><mn>1</mn></math></span> being dually-BCH codes are presented, where <em>q</em> is odd and <span><math><mi>m</mi><mo>≢</mo><mn>0</mn><mspace></mspace><mo>(</mo><mrow><mi>mod</mi></mrow><mspace></mspace><mn>4</mn><mo>)</mo></math></span>.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"99 ","pages":"Article 102478"},"PeriodicalIF":1.2,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141950539","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}
Pub Date : 2024-07-23DOI: 10.1016/j.ffa.2024.102471
Zhengbang Zha , Lei Hu
Permutation polynomials with low c-differential uniformity have important applications in cryptography and combinatorial design. In this paper, we investigate perfect c-nonlinear (PcN) and almost perfect c-nonlinear (APcN) polynomials over finite fields. Based on some known permutation polynomials, we present several classes of PcN or APcN polynomials by using the Akbary-Ghioca-Wang criterion.
具有低 c 差均匀性的置换多项式在密码学和组合设计中有着重要的应用。本文研究了有限域上的完全 c 非线性(PcN)和近似完全 c 非线性(APcN)多项式。基于一些已知的置换多项式,我们利用 Akbary-Ghioca-Wang 准则提出了几类 PcN 或 APcN 多项式。
{"title":"New results on PcN and APcN polynomials over finite fields","authors":"Zhengbang Zha , Lei Hu","doi":"10.1016/j.ffa.2024.102471","DOIUrl":"10.1016/j.ffa.2024.102471","url":null,"abstract":"<div><p>Permutation polynomials with low <em>c</em>-differential uniformity have important applications in cryptography and combinatorial design. In this paper, we investigate perfect <em>c</em>-nonlinear (PcN) and almost perfect <em>c</em>-nonlinear (APcN) polynomials over finite fields. Based on some known permutation polynomials, we present several classes of PcN or APcN polynomials by using the Akbary-Ghioca-Wang criterion.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"98 ","pages":"Article 102471"},"PeriodicalIF":1.2,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141959583","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}
Pub Date : 2024-07-18DOI: 10.1016/j.ffa.2024.102469
Xiaoer Qin , Li Yan
n-to-1 mappings have many applications in cryptography, finite geometry, coding theory and combinatorial design. In this paper, we first use cyclotomic cosets to construct several kinds of n-to-1 mappings over . Then we characterize a new form of AGW-like criterion, and use it to present many classes of n-to-1 polynomials with the form over . Finally, by using monomials on the cosets of a subgroup of and another form of AGW-like criterion, we show some n-to-1 trinomials over .
n 对 1 映射在密码学、有限几何、编码理论和组合设计中有很多应用。在本文中,我们首先利用循环余集构造了几种 Fq⁎ 上的 n 对 1 映射。然后,我们描述了一种新形式的类似 AGW 的准则,并用它提出了许多种在 Fq2⁎上具有 xrh(xq-1) 形式的 n 对 1 多项式。最后,通过使用 μq+1 子群余集上的单项式和另一种形式的类 AGW 准则,我们展示了 Fq2⁎ 上的一些 n 对 1 三项式。
{"title":"New results on n-to-1 mappings over finite fields","authors":"Xiaoer Qin , Li Yan","doi":"10.1016/j.ffa.2024.102469","DOIUrl":"10.1016/j.ffa.2024.102469","url":null,"abstract":"<div><p><em>n</em>-to-1 mappings have many applications in cryptography, finite geometry, coding theory and combinatorial design. In this paper, we first use cyclotomic cosets to construct several kinds of <em>n</em>-to-1 mappings over <span><math><msubsup><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow><mrow><mo>⁎</mo></mrow></msubsup></math></span>. Then we characterize a new form of AGW-like criterion, and use it to present many classes of <em>n</em>-to-1 polynomials with the form <span><math><msup><mrow><mi>x</mi></mrow><mrow><mi>r</mi></mrow></msup><mi>h</mi><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>q</mi><mo>−</mo><mn>1</mn></mrow></msup><mo>)</mo></math></span> over <span><math><msubsup><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>q</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow><mrow><mo>⁎</mo></mrow></msubsup></math></span>. Finally, by using monomials on the cosets of a subgroup of <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>q</mi><mo>+</mo><mn>1</mn></mrow></msub></math></span> and another form of AGW-like criterion, we show some <em>n</em>-to-1 trinomials over <span><math><msubsup><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>q</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow><mrow><mo>⁎</mo></mrow></msubsup></math></span>.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"98 ","pages":"Article 102469"},"PeriodicalIF":1.2,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141638722","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}
Pub Date : 2024-07-15DOI: 10.1016/j.ffa.2024.102467
Wen-Fong Ke , Hubert Kiechle
An explicit formula for the number of solutions of the equation in the title is given when a certain condition, depending only on the exponent and the characteristic of the field, holds. This formula improves the one given by the authors in an earlier paper.
{"title":"Circularity in finite fields and solutions of the equations xm + ym − zm = 1","authors":"Wen-Fong Ke , Hubert Kiechle","doi":"10.1016/j.ffa.2024.102467","DOIUrl":"10.1016/j.ffa.2024.102467","url":null,"abstract":"<div><p>An explicit formula for the number of solutions of the equation in the title is given when a certain condition, depending only on the exponent and the characteristic of the field, holds. This formula improves the one given by the authors in an earlier paper.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"98 ","pages":"Article 102467"},"PeriodicalIF":1.2,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141623614","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}
Pub Date : 2024-07-13DOI: 10.1016/j.ffa.2024.102466
Alexei Entin, Alexander Popov
We study the irreducibility and Galois group of random polynomials over function fields. We prove that a random polynomial with i.i.d. coefficients taking values in the set with uniform probability, is irreducible with probability tending to as , where d and q are fixed. We also prove that with the same probability, the Galois group of this random polynomial contains the alternating group . Moreover, we prove that if we assume a version of the polynomial Chowla conjecture over , then the Galois group of this polynomial is actually equal to the symmetric group with probability tending to . We also study the other possible Galois groups occurring with positive limit probability. Finally, we study the same problems with n fixed and .
{"title":"Probabilistic Galois theory in function fields","authors":"Alexei Entin, Alexander Popov","doi":"10.1016/j.ffa.2024.102466","DOIUrl":"https://doi.org/10.1016/j.ffa.2024.102466","url":null,"abstract":"<div><p>We study the irreducibility and Galois group of random polynomials over function fields. We prove that a random polynomial <span><math><mi>f</mi><mo>=</mo><msup><mrow><mi>y</mi></mrow><mrow><mi>n</mi></mrow></msup><mo>+</mo><msubsup><mrow><mo>∑</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>0</mn></mrow><mrow><mi>n</mi><mo>−</mo><mn>1</mn></mrow></msubsup><msub><mrow><mi>a</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>(</mo><mi>x</mi><mo>)</mo><msup><mrow><mi>y</mi></mrow><mrow><mi>i</mi></mrow></msup><mo>∈</mo><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub><mo>[</mo><mi>x</mi><mo>]</mo><mo>[</mo><mi>y</mi><mo>]</mo></math></span> with i.i.d. coefficients <span><math><msub><mrow><mi>a</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> taking values in the set <span><math><mo>{</mo><mi>a</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>∈</mo><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub><mo>[</mo><mi>x</mi><mo>]</mo><mo>:</mo><mi>deg</mi><mo></mo><mi>a</mi><mo>≤</mo><mi>d</mi><mo>}</mo></math></span> with uniform probability, is irreducible with probability tending to <span><math><mn>1</mn><mo>−</mo><mfrac><mrow><mn>1</mn></mrow><mrow><msup><mrow><mi>q</mi></mrow><mrow><mi>d</mi></mrow></msup></mrow></mfrac></math></span> as <span><math><mi>n</mi><mo>→</mo><mo>∞</mo></math></span>, where <em>d</em> and <em>q</em> are fixed. We also prove that with the same probability, the Galois group of this random polynomial contains the alternating group <span><math><msub><mrow><mi>A</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span>. Moreover, we prove that if we assume a version of the polynomial Chowla conjecture over <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub><mo>[</mo><mi>x</mi><mo>]</mo></math></span>, then the Galois group of this polynomial is actually equal to the symmetric group <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span> with probability tending to <span><math><mn>1</mn><mo>−</mo><mfrac><mrow><mn>1</mn></mrow><mrow><msup><mrow><mi>q</mi></mrow><mrow><mi>d</mi></mrow></msup></mrow></mfrac></math></span>. We also study the other possible Galois groups occurring with positive limit probability. Finally, we study the same problems with <em>n</em> fixed and <span><math><mi>d</mi><mo>→</mo><mo>∞</mo></math></span>.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"98 ","pages":"Article 102466"},"PeriodicalIF":1.2,"publicationDate":"2024-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141606199","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}
Pub Date : 2024-07-13DOI: 10.1016/j.ffa.2024.102468
Tongliang Zhang , Lijing Zheng , Hanbing Zhao
<div><p>Let <span><math><mi>q</mi><mo>=</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>m</mi></mrow></msup></math></span>. In this paper, we investigate permutation pentanomials over <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>q</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></msub></math></span> of the form <span><math><mi>f</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>=</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>t</mi></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>(</mo><mi>q</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>+</mo><mi>t</mi></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>(</mo><mi>q</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>+</mo><mi>t</mi></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>(</mo><mi>q</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>+</mo><mi>t</mi></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>(</mo><mi>q</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>+</mo><mi>t</mi></mrow></msup></math></span> with <span><math><mrow><mi>gcd</mi></mrow><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow></msup><mo>+</mo><mn>1</mn><mo>,</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>t</mi></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>t</mi><mo>−</mo><msub><mrow><mi>r</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>t</mi><mo>−</mo><msub><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>t</mi><mo>−</mo><msub><mrow><mi>r</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>t</mi><mo>−</mo><msub><mrow><mi>r</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msup><mo>)</mo><mo>=</mo><mn>1</mn></math></span>. We transform the problem concerning permutation property of <span><math><mi>f</mi><mo>(</mo><mi>x</mi><mo>)</mo></math></span> into demonstrating that the corresponding fractional polynomial permutes the unit circle <em>U</em> of <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>q</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></msub></math></span> with order <span><math><mi>q</mi><mo>+</mo><mn>1</mn></math></span> via a well-known lemma, and then into showing that there are no certain solution in <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></ms
{"title":"More classes of permutation pentanomials over finite fields with characteristic two","authors":"Tongliang Zhang , Lijing Zheng , Hanbing Zhao","doi":"10.1016/j.ffa.2024.102468","DOIUrl":"https://doi.org/10.1016/j.ffa.2024.102468","url":null,"abstract":"<div><p>Let <span><math><mi>q</mi><mo>=</mo><msup><mrow><mn>2</mn></mrow><mrow><mi>m</mi></mrow></msup></math></span>. In this paper, we investigate permutation pentanomials over <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>q</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></msub></math></span> of the form <span><math><mi>f</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>=</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>t</mi></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>(</mo><mi>q</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>+</mo><mi>t</mi></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>(</mo><mi>q</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>+</mo><mi>t</mi></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>3</mn></mrow></msub><mo>(</mo><mi>q</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>+</mo><mi>t</mi></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>(</mo><mi>q</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>+</mo><mi>t</mi></mrow></msup></math></span> with <span><math><mrow><mi>gcd</mi></mrow><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>r</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow></msup><mo>+</mo><mn>1</mn><mo>,</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>t</mi></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>t</mi><mo>−</mo><msub><mrow><mi>r</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>t</mi><mo>−</mo><msub><mrow><mi>r</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>t</mi><mo>−</mo><msub><mrow><mi>r</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow></msup><mo>+</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>t</mi><mo>−</mo><msub><mrow><mi>r</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msup><mo>)</mo><mo>=</mo><mn>1</mn></math></span>. We transform the problem concerning permutation property of <span><math><mi>f</mi><mo>(</mo><mi>x</mi><mo>)</mo></math></span> into demonstrating that the corresponding fractional polynomial permutes the unit circle <em>U</em> of <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>q</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></msub></math></span> with order <span><math><mi>q</mi><mo>+</mo><mn>1</mn></math></span> via a well-known lemma, and then into showing that there are no certain solution in <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></ms","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"98 ","pages":"Article 102468"},"PeriodicalIF":1.2,"publicationDate":"2024-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141606200","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}
Pub Date : 2024-07-13DOI: 10.1016/j.ffa.2024.102470
Anastasia V. Vikulova
In this paper we find the largest automorphism group of a smooth cubic surface over any finite field of characteristic 2. We prove that if the order of the field is a power of 4, then the automorphism group of maximal order of a smooth cubic surface over this field is . If the order of the field of characteristic 2 is not a power of 4, then we prove that the automorphism group of maximal order of a smooth cubic surface over this field is the symmetric group of degree 6. Moreover, we prove that smooth cubic surfaces with such properties are unique up to isomorphism.
{"title":"The most symmetric smooth cubic surface over a finite field of characteristic 2","authors":"Anastasia V. Vikulova","doi":"10.1016/j.ffa.2024.102470","DOIUrl":"https://doi.org/10.1016/j.ffa.2024.102470","url":null,"abstract":"<div><p>In this paper we find the largest automorphism group of a smooth cubic surface over any finite field of characteristic 2. We prove that if the order of the field is a power of 4, then the automorphism group of maximal order of a smooth cubic surface over this field is <span><math><msub><mrow><mi>PSU</mi></mrow><mrow><mn>4</mn></mrow></msub><mo>(</mo><msub><mrow><mi>F</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>)</mo></math></span>. If the order of the field of characteristic 2 is not a power of 4, then we prove that the automorphism group of maximal order of a smooth cubic surface over this field is the symmetric group of degree 6. Moreover, we prove that smooth cubic surfaces with such properties are unique up to isomorphism.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"98 ","pages":"Article 102470"},"PeriodicalIF":1.2,"publicationDate":"2024-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141606206","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}
Pub Date : 2024-07-08DOI: 10.1016/j.ffa.2024.102464
M. Buratti , A. Pasotti
The notion of a Heffter array, which received much attention in the last decade, is equivalent to a pair of orthogonal Heffter systems. In this paper we study the existence problem of a set of r mutually orthogonal Heffter systems for any r. Such a set is equivalent to a resolvable partial linear space of degree r whose parallel classes are Heffter systems: this is a new combinatorial design that we call a Heffter space. We present a series of direct constructions of Heffter spaces with odd block size and arbitrarily large degree r obtained with the crucial use of finite fields. Among the applications we establish, in particular, that if is a prime power with kw odd and , then there are at least mutually orthogonal k-cycle systems of order q.
赫夫特阵列的概念在过去十年中备受关注,它等价于一对正交赫夫特系统。在本文中,我们研究了任意 r 的 r 个相互正交的赫夫特系统集合的存在性问题。这样的集合等价于一个度数为 r 的可解析偏线性空间,其并行类是赫夫特系统:这是一种新的组合设计,我们称之为赫夫特空间。我们介绍了一系列直接构造的赫夫特空间,这些空间具有奇数块大小和任意大的度数 r,是利用有限域获得的。在这些应用中,我们特别指出,如果 q=2kw+1 是 kw 为奇数且 k≥3 的素数幂,那么至少有 ⌈w4k4⌉ 个相互正交的 q 阶 k 循环系统。
{"title":"Heffter spaces","authors":"M. Buratti , A. Pasotti","doi":"10.1016/j.ffa.2024.102464","DOIUrl":"https://doi.org/10.1016/j.ffa.2024.102464","url":null,"abstract":"<div><p>The notion of a Heffter array, which received much attention in the last decade, is equivalent to a pair of orthogonal Heffter systems. In this paper we study the existence problem of a set of <em>r</em> mutually orthogonal Heffter systems for any <em>r</em>. Such a set is equivalent to a resolvable partial linear space of degree <em>r</em> whose parallel classes are Heffter systems: this is a new combinatorial design that we call a <em>Heffter space</em>. We present a series of direct constructions of Heffter spaces with odd block size and arbitrarily large degree <em>r</em> obtained with the crucial use of finite fields. Among the applications we establish, in particular, that if <span><math><mi>q</mi><mo>=</mo><mn>2</mn><mi>k</mi><mi>w</mi><mo>+</mo><mn>1</mn></math></span> is a prime power with <em>kw</em> odd and <span><math><mi>k</mi><mo>≥</mo><mn>3</mn></math></span>, then there are at least <span><math><mo>⌈</mo><mfrac><mrow><mi>w</mi></mrow><mrow><mn>4</mn><msup><mrow><mi>k</mi></mrow><mrow><mn>4</mn></mrow></msup></mrow></mfrac><mo>⌉</mo></math></span> mutually orthogonal <em>k</em>-cycle systems of order <em>q</em>.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"98 ","pages":"Article 102464"},"PeriodicalIF":1.2,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141593494","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}
Pub Date : 2024-07-08DOI: 10.1016/j.ffa.2024.102465
Kathrin Bringmann , Ben Kane , Sudhir Pujahari
In this paper, we consider the moments of the trace of Frobenius of elliptic curves if the trace is restricted to a fixed arithmetic progression. We determine the asymptotic behavior for the ratio of the -th moment to the zeroeth moment as the size of the finite field goes to infinity. These results follow from similar asymptotic formulas relating sums and moments of Hurwitz class numbers where the sums are restricted to certain arithmetic progressions. As an application, we prove that the distribution of the trace of Frobenius in arithmetic progressions is equidistributed with respect to the Sato–Tate measure.
{"title":"Odd moments for the trace of Frobenius and the Sato–Tate conjecture in arithmetic progressions","authors":"Kathrin Bringmann , Ben Kane , Sudhir Pujahari","doi":"10.1016/j.ffa.2024.102465","DOIUrl":"https://doi.org/10.1016/j.ffa.2024.102465","url":null,"abstract":"<div><p>In this paper, we consider the moments of the trace of Frobenius of elliptic curves if the trace is restricted to a fixed arithmetic progression. We determine the asymptotic behavior for the ratio of the <span><math><mo>(</mo><mn>2</mn><mi>k</mi><mo>+</mo><mn>1</mn><mo>)</mo></math></span>-th moment to the zeroeth moment as the size of the finite field <span><math><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>p</mi></mrow><mrow><mi>r</mi></mrow></msup></mrow></msub></math></span> goes to infinity. These results follow from similar asymptotic formulas relating sums and moments of Hurwitz class numbers where the sums are restricted to certain arithmetic progressions. As an application, we prove that the distribution of the trace of Frobenius in arithmetic progressions is equidistributed with respect to the Sato–Tate measure.</p></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"98 ","pages":"Article 102465"},"PeriodicalIF":1.2,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141593493","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}
Pub Date : 2024-06-27DOI: 10.1016/j.ffa.2024.102451
Moubariz Z. Garaev , Igor E. Shparlinski
<div><p>Let <span><math><mi>ε</mi><mo>></mo><mn>0</mn></math></span> be a fixed small constant, <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> be the finite field of <em>p</em> elements for prime <em>p</em>. We consider additive and multiplicative problems in <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> that involve intervals and arbitrary sets. Representative examples of our results are as follows. Let <span><math><mi>M</mi></math></span> be an arbitrary subset of <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>. If <span><math><mi>#</mi><mi>M</mi><mo>></mo><msup><mrow><mi>p</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>3</mn><mo>+</mo><mi>ε</mi></mrow></msup></math></span> and <span><math><mi>H</mi><mo>⩾</mo><msup><mrow><mi>p</mi></mrow><mrow><mn>2</mn><mo>/</mo><mn>3</mn></mrow></msup></math></span> or if <span><math><mi>#</mi><mi>M</mi><mo>></mo><msup><mrow><mi>p</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>5</mn><mo>+</mo><mi>ε</mi></mrow></msup></math></span> and <span><math><mi>H</mi><mo>⩾</mo><msup><mrow><mi>p</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>5</mn><mo>+</mo><mi>ε</mi></mrow></msup></math></span> then all, but <span><math><mi>O</mi><mo>(</mo><msup><mrow><mi>p</mi></mrow><mrow><mn>1</mn><mo>−</mo><mi>δ</mi></mrow></msup><mo>)</mo></math></span> elements of <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> can be represented in the form <em>hm</em> with <span><math><mi>h</mi><mo>∈</mo><mo>[</mo><mn>1</mn><mo>,</mo><mi>H</mi><mo>]</mo></math></span> and <span><math><mi>m</mi><mo>∈</mo><mi>M</mi></math></span>, where <span><math><mi>δ</mi><mo>></mo><mn>0</mn></math></span> depends only on <em>ε</em>. Furthermore, let <span><math><mi>X</mi></math></span> be an arbitrary interval of length <em>H</em> and <em>s</em> be a fixed positive integer. If<span><span><span><math><mi>H</mi><mo>></mo><msup><mrow><mi>p</mi></mrow><mrow><mn>17</mn><mo>/</mo><mn>35</mn><mo>+</mo><mi>ε</mi></mrow></msup><mo>,</mo><mspace></mspace><mi>#</mi><mi>M</mi><mo>></mo><msup><mrow><mi>p</mi></mrow><mrow><mn>17</mn><mo>/</mo><mn>35</mn><mo>+</mo><mi>ε</mi></mrow></msup><mo>,</mo></math></span></span></span> then the number <span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>6</mn></mrow></msub><mo>(</mo><mi>λ</mi><mo>)</mo></math></span> of solutions to the congruence<span><span><span><math><mfrac><mrow><msub><mrow><mi>m</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow><mrow><msubsup><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow><mrow><mi>s</mi></mrow></msubsup></mrow></mfrac><mo>+</mo><mfrac><mrow><msub><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mrow><msubsup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow><mrow><mi>s</mi></mrow></msubsup></mrow></mfrac><mo>+</mo><mfrac><mrow><msub><mrow><mi>m</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow><mrow><msubsup><mrow><mi>x</mi></mrow><mrow><mn>3
让 ε>0 是一个固定的小常数,Fp 是素数 p 的 p 元素有限域。我们考虑 Fp 中涉及区间和任意集合的加法和乘法问题。我们的代表性结果举例如下。设 M 是 Fp 的任意子集。如果 #M>p1/3+ε 和 H⩾p2/3,或者如果 #M>p3/5+ε 和 H⩾p3/5+ε,那么除了 O(p1-δ)个元素外,Fp 的所有元素都可以用 hm 的形式表示,其中 h∈[1,H],m∈M,δ>0 只取决于 ε。此外,设 X 是长度为 H 的任意区间,s 是一个固定的正整数。若 H>p17/35+ε,#M>p17/35+ε,则全等m1x1s+m2x2s+m3x3s+m4x4s+m5x5s+m6x6s≡λmodp,mi∈M,xi∈X,i=1,...,6 的解的个数 T6(λ)满足T6(λ)=H6(#M)6p(1+O(p-δ))。
{"title":"On some congruences and exponential sums","authors":"Moubariz Z. Garaev , Igor E. Shparlinski","doi":"10.1016/j.ffa.2024.102451","DOIUrl":"https://doi.org/10.1016/j.ffa.2024.102451","url":null,"abstract":"<div><p>Let <span><math><mi>ε</mi><mo>></mo><mn>0</mn></math></span> be a fixed small constant, <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> be the finite field of <em>p</em> elements for prime <em>p</em>. We consider additive and multiplicative problems in <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> that involve intervals and arbitrary sets. Representative examples of our results are as follows. Let <span><math><mi>M</mi></math></span> be an arbitrary subset of <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>. If <span><math><mi>#</mi><mi>M</mi><mo>></mo><msup><mrow><mi>p</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>3</mn><mo>+</mo><mi>ε</mi></mrow></msup></math></span> and <span><math><mi>H</mi><mo>⩾</mo><msup><mrow><mi>p</mi></mrow><mrow><mn>2</mn><mo>/</mo><mn>3</mn></mrow></msup></math></span> or if <span><math><mi>#</mi><mi>M</mi><mo>></mo><msup><mrow><mi>p</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>5</mn><mo>+</mo><mi>ε</mi></mrow></msup></math></span> and <span><math><mi>H</mi><mo>⩾</mo><msup><mrow><mi>p</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>5</mn><mo>+</mo><mi>ε</mi></mrow></msup></math></span> then all, but <span><math><mi>O</mi><mo>(</mo><msup><mrow><mi>p</mi></mrow><mrow><mn>1</mn><mo>−</mo><mi>δ</mi></mrow></msup><mo>)</mo></math></span> elements of <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span> can be represented in the form <em>hm</em> with <span><math><mi>h</mi><mo>∈</mo><mo>[</mo><mn>1</mn><mo>,</mo><mi>H</mi><mo>]</mo></math></span> and <span><math><mi>m</mi><mo>∈</mo><mi>M</mi></math></span>, where <span><math><mi>δ</mi><mo>></mo><mn>0</mn></math></span> depends only on <em>ε</em>. Furthermore, let <span><math><mi>X</mi></math></span> be an arbitrary interval of length <em>H</em> and <em>s</em> be a fixed positive integer. If<span><span><span><math><mi>H</mi><mo>></mo><msup><mrow><mi>p</mi></mrow><mrow><mn>17</mn><mo>/</mo><mn>35</mn><mo>+</mo><mi>ε</mi></mrow></msup><mo>,</mo><mspace></mspace><mi>#</mi><mi>M</mi><mo>></mo><msup><mrow><mi>p</mi></mrow><mrow><mn>17</mn><mo>/</mo><mn>35</mn><mo>+</mo><mi>ε</mi></mrow></msup><mo>,</mo></math></span></span></span> then the number <span><math><msub><mrow><mi>T</mi></mrow><mrow><mn>6</mn></mrow></msub><mo>(</mo><mi>λ</mi><mo>)</mo></math></span> of solutions to the congruence<span><span><span><math><mfrac><mrow><msub><mrow><mi>m</mi></mrow><mrow><mn>1</mn></mrow></msub></mrow><mrow><msubsup><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow><mrow><mi>s</mi></mrow></msubsup></mrow></mfrac><mo>+</mo><mfrac><mrow><msub><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mrow><msubsup><mrow><mi>x</mi></mrow><mrow><mn>2</mn></mrow><mrow><mi>s</mi></mrow></msubsup></mrow></mfrac><mo>+</mo><mfrac><mrow><msub><mrow><mi>m</mi></mrow><mrow><mn>3</mn></mrow></msub></mrow><mrow><msubsup><mrow><mi>x</mi></mrow><mrow><mn>3","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"98 ","pages":"Article 102451"},"PeriodicalIF":1.2,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S107157972400090X/pdfft?md5=73d751bad88083ca796c715f3b4d9bad&pid=1-s2.0-S107157972400090X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141485792","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}