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An Extension of Craig's Family of Lattices

Published online by Cambridge University Press:  20 November 2018

André Luiz Flores
Affiliation:
Departamento de Matemática, Universidade Federal de Alagoas, Arapiraca, AL, Brazile-mail: andreflores br@yahoo.com.br
J. Carmelo Interlando
Affiliation:
Department of Mathematics and Statistics, San Diego State University, San Diego, CA, U.S.A.e-mail: carmelo.interlando@sdsu.edu
Trajano Pires da Nóbrega Neto
Affiliation:
Departamento de Matemática, Universidade Estadual Paulista, São José do Rio Preto, SP, Brazile-mail: trajano@ibilce.unesp.br
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Abstract

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Let $p$ be a prime, and let ${{\zeta }_{p}}$ be a primitive $p$-th root of unity. The lattices in Craig's family are $(p\,-\,1)$-dimensional and are geometrical representations of the integral $\mathbb{Z}[{{\zeta }_{p}}]$-ideals ${{\left\langle 1\,-\,{{\zeta }_{p}} \right\rangle }^{i}}$, where $i$ is a positive integer. This lattice construction technique is a powerful one. Indeed, in dimensions $p\,-\,1$ where $149\,\le \,p\,\le \,3001$, Craig's lattices are the densest packings known. Motivated by this, we construct $(p\,-\,1)(q\,-\,1)$-dimensional lattices from the integral $\mathbb{Z}[{{\zeta }_{pq}}]$-ideals ${{\left\langle 1\,-\,{{\zeta }_{p}} \right\rangle }^{i}}{{\left\langle 1\,-\,{{\zeta }_{q}} \right\rangle }^{j}}$, where $p$ and $q$ are distinct primes and $i$ and $j$ are positive integers. In terms of sphere-packing density, the new lattices and those in Craig's family have the same asymptotic behavior. In conclusion, Craig's family is greatly extended while preserving its sphere-packing properties.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 2011

References

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