Several Goethals–Seidel Sequences with Special Structures

In this paper, we develop a novel method to construct Goethals–Seidel (GS) sequences with special structures. In the existing methods, utilizing Turyn sequences is an effective and convenient approach; however, this method cannot cover all GS sequences. Motivated by this, we are devoted to designing...

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Main Authors: Shuhui Shen, Xiaojun Zhang
Format: Article
Language:English
Published: MDPI AG 2024-02-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/12/4/530
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author Shuhui Shen
Xiaojun Zhang
author_facet Shuhui Shen
Xiaojun Zhang
author_sort Shuhui Shen
collection DOAJ
description In this paper, we develop a novel method to construct Goethals–Seidel (GS) sequences with special structures. In the existing methods, utilizing Turyn sequences is an effective and convenient approach; however, this method cannot cover all GS sequences. Motivated by this, we are devoted to designing some sequences that can potentially construct all GS sequences. Firstly, it is proven that a quad of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>±</mo><mn>1</mn></mrow></semantics></math></inline-formula> polynomials can be considered a linear combination of eight polynomials with coefficients uniquely belonging to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>{</mo><mn>0</mn><mo>,</mo><mo>±</mo><mn>1</mn><mo>}</mo></mrow></semantics></math></inline-formula>. Based on this fact, we change the construction of a quad of Goethals–Seidel sequences to find eight sequences consisting of 0 and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>±</mo><mn>1</mn></mrow></semantics></math></inline-formula>. One more motivation is to obtain these sequences more efficiently. To this end, we make use of the <i>k</i>-block, of which some properties of (anti) symmetry are discussed. After this, we can then look for the sequences with the help of computers since the symmetry properties facilitate reducing the search range. Moreover, we find that one of the eight blocks, which we utilize to construct GS sequences directly, can also be combined with Williamson sequences to generate GS sequences with more order. Several examples are provided to verify the theoretical results. The main contribution of this work is in building a bridge linking the GS sequences and eight polynomials, and the paper also provides a novel insight through which to consider the existence of GS sequences.
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spelling doaj.art-82a98d8c19304bac998865b59e1b170d2024-02-23T15:26:04ZengMDPI AGMathematics2227-73902024-02-0112453010.3390/math12040530Several Goethals–Seidel Sequences with Special StructuresShuhui Shen0Xiaojun Zhang1School of Mathematical Sciences, University of Electronic Science and Technology of China, Chengdu 611731, ChinaSchool of Mathematical Sciences, University of Electronic Science and Technology of China, Chengdu 611731, ChinaIn this paper, we develop a novel method to construct Goethals–Seidel (GS) sequences with special structures. In the existing methods, utilizing Turyn sequences is an effective and convenient approach; however, this method cannot cover all GS sequences. Motivated by this, we are devoted to designing some sequences that can potentially construct all GS sequences. Firstly, it is proven that a quad of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>±</mo><mn>1</mn></mrow></semantics></math></inline-formula> polynomials can be considered a linear combination of eight polynomials with coefficients uniquely belonging to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>{</mo><mn>0</mn><mo>,</mo><mo>±</mo><mn>1</mn><mo>}</mo></mrow></semantics></math></inline-formula>. Based on this fact, we change the construction of a quad of Goethals–Seidel sequences to find eight sequences consisting of 0 and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>±</mo><mn>1</mn></mrow></semantics></math></inline-formula>. One more motivation is to obtain these sequences more efficiently. To this end, we make use of the <i>k</i>-block, of which some properties of (anti) symmetry are discussed. After this, we can then look for the sequences with the help of computers since the symmetry properties facilitate reducing the search range. Moreover, we find that one of the eight blocks, which we utilize to construct GS sequences directly, can also be combined with Williamson sequences to generate GS sequences with more order. Several examples are provided to verify the theoretical results. The main contribution of this work is in building a bridge linking the GS sequences and eight polynomials, and the paper also provides a novel insight through which to consider the existence of GS sequences.https://www.mdpi.com/2227-7390/12/4/530Goethals–Seidel sequencesk-block and k-partitionsymmetry and antisymmetry
spellingShingle Shuhui Shen
Xiaojun Zhang
Several Goethals–Seidel Sequences with Special Structures
Mathematics
Goethals–Seidel sequences
k-block and k-partition
symmetry and antisymmetry
title Several Goethals–Seidel Sequences with Special Structures
title_full Several Goethals–Seidel Sequences with Special Structures
title_fullStr Several Goethals–Seidel Sequences with Special Structures
title_full_unstemmed Several Goethals–Seidel Sequences with Special Structures
title_short Several Goethals–Seidel Sequences with Special Structures
title_sort several goethals seidel sequences with special structures
topic Goethals–Seidel sequences
k-block and k-partition
symmetry and antisymmetry
url https://www.mdpi.com/2227-7390/12/4/530
work_keys_str_mv AT shuhuishen severalgoethalsseidelsequenceswithspecialstructures
AT xiaojunzhang severalgoethalsseidelsequenceswithspecialstructures