Pub Date : 2026-01-19DOI: 10.1016/j.ffa.2026.102795
Jingjun Bao , Hanlin Zou
Cyclic codes are an important subclass of linear codes with wide applications in communication systems and data storage systems. In 2013, Ding and Helleseth presented nine open problems on optimal ternary cyclic codes . While the first two and the sixth problems have been fully solved, others remain open. In this paper, we advance the study of the third and fourth open problems by providing the first counterexamples to both and constructing two families of optimal codes under certain conditions, thereby partially solving the third problem. Furthermore, we investigate the cyclic codes where and a is odd. For , we present two new families of optimal codes with parameters , generalizing known constructions. For , we obtain several nonexistence results on optimal codes with the aforementioned parameters revealing the constraints of such codes.
{"title":"Counterexamples, constructions, and nonexistence results for optimal ternary cyclic codes","authors":"Jingjun Bao , Hanlin Zou","doi":"10.1016/j.ffa.2026.102795","DOIUrl":"10.1016/j.ffa.2026.102795","url":null,"abstract":"<div><div>Cyclic codes are an important subclass of linear codes with wide applications in communication systems and data storage systems. In 2013, Ding and Helleseth presented nine open problems on optimal ternary cyclic codes <span><math><msub><mrow><mi>C</mi></mrow><mrow><mo>(</mo><mn>1</mn><mo>,</mo><mi>e</mi><mo>)</mo></mrow></msub></math></span>. While the first two and the sixth problems have been fully solved, others remain open. In this paper, we advance the study of the third and fourth open problems by providing the first counterexamples to both and constructing two families of optimal codes under certain conditions, thereby partially solving the third problem. Furthermore, we investigate the cyclic codes <span><math><msub><mrow><mi>C</mi></mrow><mrow><mo>(</mo><mn>1</mn><mo>,</mo><mi>e</mi><mo>)</mo></mrow></msub></math></span> where <span><math><mi>e</mi><mo>(</mo><msup><mrow><mn>3</mn></mrow><mrow><mi>h</mi></mrow></msup><mo>±</mo><mn>1</mn><mo>)</mo><mo>≡</mo><mfrac><mrow><msup><mrow><mn>3</mn></mrow><mrow><mi>m</mi></mrow></msup><mo>−</mo><mi>a</mi></mrow><mrow><mn>2</mn></mrow></mfrac><mspace></mspace><mo>(</mo><mrow><mi>mod</mi></mrow><mspace></mspace><msup><mrow><mn>3</mn></mrow><mrow><mi>m</mi></mrow></msup><mo>−</mo><mn>1</mn><mo>)</mo></math></span> and <em>a</em> is odd. For <span><math><mi>a</mi><mo>≡</mo><mn>3</mn><mspace></mspace><mo>(</mo><mrow><mi>mod</mi></mrow><mspace></mspace><mn>4</mn><mo>)</mo></math></span>, we present two new families of optimal codes with parameters <span><math><mo>[</mo><msup><mrow><mn>3</mn></mrow><mrow><mi>m</mi></mrow></msup><mo>−</mo><mn>1</mn><mo>,</mo><msup><mrow><mn>3</mn></mrow><mrow><mi>m</mi></mrow></msup><mo>−</mo><mn>1</mn><mo>−</mo><mn>2</mn><mi>m</mi><mo>,</mo><mn>4</mn><mo>]</mo></math></span>, generalizing known constructions. For <span><math><mi>a</mi><mo>≡</mo><mn>1</mn><mspace></mspace><mo>(</mo><mrow><mi>mod</mi></mrow><mspace></mspace><mn>4</mn><mo>)</mo></math></span>, we obtain several nonexistence results on optimal codes <span><math><msub><mrow><mi>C</mi></mrow><mrow><mo>(</mo><mn>1</mn><mo>,</mo><mi>e</mi><mo>)</mo></mrow></msub></math></span> with the aforementioned parameters revealing the constraints of such codes.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"112 ","pages":"Article 102795"},"PeriodicalIF":1.2,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039254","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 : 2026-01-19DOI: 10.1016/j.ffa.2026.102796
Xiutao Feng , Qiang Wang
We provide a generic construction of permutation polynomials over with index from any permutation polynomial of . We also extend our construction using polynomials with coefficients in such that they are injective over a subset of , which corresponds to the set of all -th roots of unity.
{"title":"Permutation polynomials of index q + 1 over Fq2","authors":"Xiutao Feng , Qiang Wang","doi":"10.1016/j.ffa.2026.102796","DOIUrl":"10.1016/j.ffa.2026.102796","url":null,"abstract":"<div><div>We provide a generic construction of permutation polynomials 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> with index <span><math><mi>q</mi><mo>+</mo><mn>1</mn></math></span> from any permutation polynomial of <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span>. We also extend our construction using polynomials with coefficients in <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> such that they are injective over a subset of <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>, which corresponds to the set <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>q</mi><mo>+</mo><mn>1</mn></mrow></msub></math></span> of all <span><math><mo>(</mo><mi>q</mi><mo>+</mo><mn>1</mn><mo>)</mo></math></span>-th roots of unity.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"112 ","pages":"Article 102796"},"PeriodicalIF":1.2,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039253","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 : 2026-01-19DOI: 10.1016/j.ffa.2026.102793
Owen J. Brison , J. Eurico Nogueira
We study the behaviour with respect to the operation of lifting of the unit g-sequence, where is a primitive polynomial. We also study the unit f-sequence for primitive-based and show it is closely related to the lifted unit g-sequence where is based on .
{"title":"The unit f-sequence for primitive-based f","authors":"Owen J. Brison , J. Eurico Nogueira","doi":"10.1016/j.ffa.2026.102793","DOIUrl":"10.1016/j.ffa.2026.102793","url":null,"abstract":"<div><div>We study the behaviour with respect to the operation of lifting of the unit <em>g</em>-sequence, where <span><math><mi>g</mi><mo>(</mo><mi>t</mi><mo>)</mo></math></span> is a primitive polynomial. We also study the unit <em>f</em>-sequence for primitive-based <span><math><mi>f</mi><mo>(</mo><mi>t</mi><mo>)</mo></math></span> and show it is closely related to the lifted unit <em>g</em>-sequence where <span><math><mi>f</mi><mo>(</mo><mi>t</mi><mo>)</mo></math></span> is based on <span><math><mi>g</mi><mo>(</mo><mi>t</mi><mo>)</mo></math></span>.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"112 ","pages":"Article 102793"},"PeriodicalIF":1.2,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039256","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 : 2026-01-19DOI: 10.1016/j.ffa.2026.102798
Heming Cui , Xubo Zhao , Qiang Wang , Xiaoping Li , Tongjiang Yan
Linear codes with few weights have attracted significant interest due to their wide-ranging applications in secret sharing, authentication codes, association schemes, strongly regular graph, and some other fields. This paper focuses on unifying several existing construction methods for few-weight linear codes, extending the works of Wang et al. (2015) [24], Wu et al. (2019) [25], and Fang et al. (2023) [10]. In our code construction, we introduce a novel index set , whose cardinality and structural properties are shown to critically influence both the length and weight distribution of the resulting few-weight linear codes. By employing cyclotomic mappings and choosing the more general defining sets, several new classes of binary linear codes with at most three weights are constructed. Our framework subsumes all aforementioned constructions as special cases and enlarges the spectrum of attainable parameters. The weight distributions of the corresponding linear codes are also explicitly determined. We also demonstrate that some of the linear codes constructed in this paper are optimal in the sense that they have the best known parameters in the tables maintained by Markus Grassl and/or optimal in the sense that they meet certain bounds on linear codes.
{"title":"Binary linear codes with at most three weights from cyclotomic mappings","authors":"Heming Cui , Xubo Zhao , Qiang Wang , Xiaoping Li , Tongjiang Yan","doi":"10.1016/j.ffa.2026.102798","DOIUrl":"10.1016/j.ffa.2026.102798","url":null,"abstract":"<div><div>Linear codes with few weights have attracted significant interest due to their wide-ranging applications in secret sharing, authentication codes, association schemes, strongly regular graph, and some other fields. This paper focuses on unifying several existing construction methods for few-weight linear codes, extending the works of Wang et al. (2015) <span><span>[24]</span></span>, Wu et al. (2019) <span><span>[25]</span></span>, and Fang et al. (2023) <span><span>[10]</span></span>. In our code construction, we introduce a novel index set <span><math><mi>J</mi></math></span>, whose cardinality and structural properties are shown to critically influence both the length and weight distribution of the resulting few-weight linear codes. By employing cyclotomic mappings and choosing the more general defining sets, several new classes of binary linear codes with at most three weights are constructed. Our framework subsumes all aforementioned constructions as special cases and enlarges the spectrum of attainable parameters. The weight distributions of the corresponding linear codes are also explicitly determined. We also demonstrate that some of the linear codes constructed in this paper are optimal in the sense that they have the best known parameters in the tables maintained by Markus Grassl and/or optimal in the sense that they meet certain bounds on linear codes.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"112 ","pages":"Article 102798"},"PeriodicalIF":1.2,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039255","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 : 2026-01-16DOI: 10.1016/j.ffa.2026.102794
Gábor Korchmáros , Federico Romaniello , Valentino Smaldore
Algebraic geometry codes on the Hermitian curve have been the subject of several papers, since they happen to have good performances and large automorphism groups. Here, those arising from the Singer cycle of the Hermitian curve are investigated.
{"title":"Hermitian-Singer functional and differential codes","authors":"Gábor Korchmáros , Federico Romaniello , Valentino Smaldore","doi":"10.1016/j.ffa.2026.102794","DOIUrl":"10.1016/j.ffa.2026.102794","url":null,"abstract":"<div><div>Algebraic geometry codes on the Hermitian curve have been the subject of several papers, since they happen to have good performances and large automorphism groups. Here, those arising from the Singer cycle of the Hermitian curve are investigated.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"112 ","pages":"Article 102794"},"PeriodicalIF":1.2,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981221","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 : 2026-01-15DOI: 10.1016/j.ffa.2026.102790
Ming Hsuan Kang, Yu Hsuan Hsieh
We present an algebraic construction of trace-based De Bruijn tori over finite fields, focusing on the nonzero variant that omits the all-zero pattern. The construction arranges nonzero field elements on a toroidal grid using two multiplicatively independent generators, with values obtained by applying a fixed linear map, typically the field trace.
We characterize sampling patterns as subsets whose associated field elements form an -basis, and show that column structures correspond to cyclic shifts of De Bruijn sequences determined by irreducible polynomials over subfields. Recursive update rules based on multiplicative translations enable efficient computation.
{"title":"De Bruijn tori without zeros: a field-theoretic perspective","authors":"Ming Hsuan Kang, Yu Hsuan Hsieh","doi":"10.1016/j.ffa.2026.102790","DOIUrl":"10.1016/j.ffa.2026.102790","url":null,"abstract":"<div><div>We present an algebraic construction of trace-based De Bruijn tori over finite fields, focusing on the nonzero variant that omits the all-zero pattern. The construction arranges nonzero field elements on a toroidal grid using two multiplicatively independent generators, with values obtained by applying a fixed linear map, typically the field trace.</div><div>We characterize sampling patterns as subsets whose associated field elements form an <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>p</mi></mrow></msub></math></span>-basis, and show that column structures correspond to cyclic shifts of De Bruijn sequences determined by irreducible polynomials over subfields. Recursive update rules based on multiplicative translations enable efficient computation.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"112 ","pages":"Article 102790"},"PeriodicalIF":1.2,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981218","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 : 2026-01-15DOI: 10.1016/j.ffa.2026.102799
Clementa Alonso-González, Miguel Ángel Navarro-Pérez
A flag is a sequence of nested subspaces of a given ambient space over a finite field . In network coding, a flag code is a set of flags, all of them with the same sequence of dimensions, the type vector. In this paper, we investigate quasi-optimum distance flag codes, i.e., those attaining the second best possible distance value. We characterize them and present upper bounds for their cardinality. Moreover, we propose a systematic construction for every choice of the type vector by using partial spreads and sunflowers. For flag codes with lower minimum distance, we adapt the previous construction and provide some results towards their characterization, especially in the case of the third best possible distance value.
{"title":"Quasi-optimum distance flag codes","authors":"Clementa Alonso-González, Miguel Ángel Navarro-Pérez","doi":"10.1016/j.ffa.2026.102799","DOIUrl":"10.1016/j.ffa.2026.102799","url":null,"abstract":"<div><div>A <em>flag</em> is a sequence of nested subspaces of a given ambient space <span><math><msubsup><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow><mrow><mi>n</mi></mrow></msubsup></math></span> over a finite field <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span>. In network coding, a <em>flag code</em> is a set of flags, all of them with the same sequence of dimensions, the <em>type vector</em>. In this paper, we investigate <em>quasi-optimum distance flag codes</em>, i.e., those attaining the second best possible distance value. We characterize them and present upper bounds for their cardinality. Moreover, we propose a systematic construction for every choice of the type vector by using <em>partial spreads</em> and <em>sunflowers</em>. For flag codes with lower minimum distance, we adapt the previous construction and provide some results towards their characterization, especially in the case of the third best possible distance value.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"112 ","pages":"Article 102799"},"PeriodicalIF":1.2,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981220","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 : 2026-01-14DOI: 10.1016/j.ffa.2026.102797
Rohit Gupta , Amritanshu Rai
Let q be a power of a prime number and let be the finite field with q elements. Let be arbitrary. In this paper, we give a relationship between the permutation property of polynomials over of the forms and where , . Further, we find the necessary and sufficient conditions on the coefficients c and d such that polynomials of the forms and permute . Moreover, some results of this article supersede certain results in the related literature.
{"title":"Permutation polynomials of the form (xq−x+δ)i(q−1)+1+L(x) over Fq2","authors":"Rohit Gupta , Amritanshu Rai","doi":"10.1016/j.ffa.2026.102797","DOIUrl":"10.1016/j.ffa.2026.102797","url":null,"abstract":"<div><div>Let <em>q</em> be a power of a prime number and let <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span> be the finite field with <em>q</em> elements. Let <span><math><mi>δ</mi><mo>∈</mo><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>q</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></msub></math></span> be arbitrary. In this paper, we give a relationship between the permutation property of polynomials 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 forms <span><math><mi>g</mi><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>q</mi></mrow></msup><mo>−</mo><mi>x</mi><mo>+</mo><mi>δ</mi><mo>)</mo><mo>+</mo><mi>c</mi><msup><mrow><mi>x</mi></mrow><mrow><mi>q</mi></mrow></msup><mo>+</mo><mi>d</mi><mi>x</mi></math></span> and <span><math><mi>g</mi><msup><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow><mrow><mi>q</mi></mrow></msup><mo>−</mo><mi>g</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>+</mo><mi>c</mi><msup><mrow><mi>x</mi></mrow><mrow><mi>q</mi></mrow></msup><mo>+</mo><mi>d</mi><mi>x</mi></math></span> where <span><math><mi>c</mi><mo>,</mo><mi>d</mi><mo>∈</mo><msubsup><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow><mrow><mo>⁎</mo></mrow></msubsup></math></span>, <span><math><mi>g</mi><mo>(</mo><mi>x</mi><mo>)</mo><mo>∈</mo><msub><mrow><mi>F</mi></mrow><mrow><msup><mrow><mi>q</mi></mrow><mrow><mn>2</mn></mrow></msup></mrow></msub><mo>[</mo><mi>x</mi><mo>]</mo></math></span>. Further, we find the necessary and sufficient conditions on the coefficients <em>c</em> and <em>d</em> such that polynomials of the forms <span><math><msup><mrow><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>q</mi></mrow></msup><mo>−</mo><mi>x</mi><mo>+</mo><mi>δ</mi><mo>)</mo></mrow><mrow><mi>i</mi><mo>(</mo><mi>q</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>+</mo><mn>1</mn></mrow></msup><mo>+</mo><mi>c</mi><mi>x</mi></math></span> and <span><math><msup><mrow><mo>(</mo><msup><mrow><mi>x</mi></mrow><mrow><mi>q</mi></mrow></msup><mo>−</mo><mi>x</mi><mo>+</mo><mi>δ</mi><mo>)</mo></mrow><mrow><mi>i</mi><mo>(</mo><mi>q</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>+</mo><mn>1</mn></mrow></msup><mo>+</mo><mi>c</mi><msup><mrow><mi>x</mi></mrow><mrow><mi>q</mi></mrow></msup><mo>+</mo><mi>d</mi><mi>x</mi></math></span> permute <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>. Moreover, some results of this article supersede certain results in the related literature.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"112 ","pages":"Article 102797"},"PeriodicalIF":1.2,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981222","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 : 2026-01-13DOI: 10.1016/j.ffa.2026.102791
Huiying Liu, Hongwei Liu
Function-correcting codes are designed to reduce redundancy of codes when protecting function values of information against errors. As generalizations of Hamming weights and Lee weights over , homogeneous weights are used in codes over finite rings. In this paper, we introduce function-correcting codes with homogeneous distance denoted by FCCHDs, which extend function-correcting codes with Hamming distance. We first define D-homogeneous distance codes. We use D-homogeneous distance codes to characterize connections between the optimal redundancy of FCCHDs and lengths of these codes for some matrices D. By these connections, we obtain several bounds of the optimal redundancy of FCCHDs for some functions. In addition, we also construct FCCHDs for homogeneous weight functions and homogeneous weight distribution functions. Specially, redundancies of some codes we construct in this paper reach the optimal redundancy bounds.
{"title":"Function-correcting codes with homogeneous distance","authors":"Huiying Liu, Hongwei Liu","doi":"10.1016/j.ffa.2026.102791","DOIUrl":"10.1016/j.ffa.2026.102791","url":null,"abstract":"<div><div>Function-correcting codes are designed to reduce redundancy of codes when protecting function values of information against errors. As generalizations of Hamming weights and Lee weights over <span><math><msub><mrow><mi>Z</mi></mrow><mrow><mn>4</mn></mrow></msub></math></span>, homogeneous weights are used in codes over finite rings. In this paper, we introduce function-correcting codes with homogeneous distance denoted by FCCHDs, which extend function-correcting codes with Hamming distance. We first define <em>D</em>-homogeneous distance codes. We use <em>D</em>-homogeneous distance codes to characterize connections between the optimal redundancy of FCCHDs and lengths of these codes for some matrices <em>D</em>. By these connections, we obtain several bounds of the optimal redundancy of FCCHDs for some functions. In addition, we also construct FCCHDs for homogeneous weight functions and homogeneous weight distribution functions. Specially, redundancies of some codes we construct in this paper reach the optimal redundancy bounds.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"112 ","pages":"Article 102791"},"PeriodicalIF":1.2,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950123","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 : 2026-01-13DOI: 10.1016/j.ffa.2026.102792
André Duarte
Let be a finite field and is the dihedral group of order 2n. We present formulas for a complete set of 2-cocycles of over and compute the primitive central idempotents of . We conclude by describing the Wedderburn decomposition of and the irreducible projective representations of over .
{"title":"Twisted group algebra of dihedral groups over finite fields","authors":"André Duarte","doi":"10.1016/j.ffa.2026.102792","DOIUrl":"10.1016/j.ffa.2026.102792","url":null,"abstract":"<div><div>Let <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span> be a finite field and <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span> is the dihedral group of order 2<em>n</em>. We present formulas for a complete set of 2-cocycles of <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span> over <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span> and compute the primitive central idempotents of <span><math><msubsup><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow><mrow><mi>α</mi></mrow></msubsup><msub><mrow><mi>D</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span>. We conclude by describing the Wedderburn decomposition of <span><math><msubsup><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow><mrow><mi>α</mi></mrow></msubsup><msub><mrow><mi>D</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span> and the irreducible projective representations of <span><math><msub><mrow><mi>D</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span> over <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>q</mi></mrow></msub></math></span>.</div></div>","PeriodicalId":50446,"journal":{"name":"Finite Fields and Their Applications","volume":"112 ","pages":"Article 102792"},"PeriodicalIF":1.2,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145950124","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}