Semidefinite bounds for nonbinary codes based on quadruples
Autor: | Alexander Schrijver, Bart Litjens, Sven Polak |
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Přispěvatelé: | Algebra, Geometry & Mathematical Physics (KDV, FNWI), Faculty of Science |
Rok vydání: | 2016 |
Předmět: |
Upper bounds
Nonbinary code 0102 computer and information sciences 02 engineering and technology Positive-definite matrix 90C22 01 natural sciences Upper and lower bounds Representation theory Article Combinatorics Cardinality FOS: Mathematics 0202 electrical engineering electronic engineering information engineering Mathematics - Combinatorics Semidefinite programming Representation Theory (math.RT) Mathematics - Optimization and Control Mathematics Polynomial (hyperelastic model) Code Applied Mathematics Order (ring theory) 020206 networking & telecommunications Function (mathematics) 94B65 05E10 90C22 20C30 Computer Science Applications Optimization and Control (math.OC) 010201 computation theory & mathematics Bounded function Delsarte 94B65 Combinatorics (math.CO) 20C30 05E10 Mathematics - Representation Theory |
Zdroj: | Designs, Codes, and Cryptography Designs, Codes and Cryptography, 84, 87-100 Designs, Codes and Cryptography, 84(1-2), 87-100. Springer Netherlands |
ISSN: | 1573-7586 0925-1022 |
DOI: | 10.1007/s10623-016-0216-5 |
Popis: | For nonnegative integers q, n, d, let \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$A_q(n,d)$$\end{document}Aq(n,d) denote the maximum cardinality of a code of length n over an alphabet [q] with q letters and with minimum distance at least d. We consider the following upper bound on \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$A_q(n,d)$$\end{document}Aq(n,d). For any k, let \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal{C}_k$$\end{document}Ck be the collection of codes of cardinality at most k. Then \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$A_q(n,d)$$\end{document}Aq(n,d) is at most the maximum value of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sum _{v\in [q]^n}x(\{v\})$$\end{document}∑v∈[q]nx({v}), where x is a function \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal{C}_4\rightarrow {\mathbb {R}}_+$$\end{document}C4→R+ such that \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$x(\emptyset )=1$$\end{document}x(∅)=1 and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$x(C)=\!0$$\end{document}x(C)=0 if C has minimum distance less than d, and such that the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\mathcal{C}_2\times \mathcal{C}_2$$\end{document}C2×C2 matrix \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$(x(C\cup C'))_{C,C'\in \mathcal{C}_2}$$\end{document}(x(C∪C′))C,C′∈C2 is positive semidefinite. By the symmetry of the problem, we can apply representation theory to reduce the problem to a semidefinite programming problem with order bounded by a polynomial in n. It yields the new upper bounds \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$A_4(6,3)\le 176$$\end{document}A4(6,3)≤176, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$A_4(7,3)\le 596$$\end{document}A4(7,3)≤596, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$A_4(7,4)\le 155$$\end{document}A4(7,4)≤155, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$A_5(7,4)\le 489$$\end{document}A5(7,4)≤489, and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$A_5(7,5)\le 87$$\end{document}A5(7,5)≤87. |
Databáze: | OpenAIRE |
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