How many sublattices of index N are there in the planar hexagonal lattice? Which of them are the best from the point of view of packing density, signal-to-noise ratio, or energy? We answer the first question completely and give partial answers to the other questions.
Sublattices of the Lattice of Pre-natural Classes of Modules
โ Scribed by John Dauns; Yiqiang Zhou
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 207 KB
- Volume
- 231
- Category
- Article
- ISSN
- 0021-8693
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โฆ Synopsis
A pre-natural class of modules over a ring R is one that is closed under isomorphic copies, submodules, arbitrary direct sums, and certain essential extensions. The set p r R of all pre-natural classes is a lattice, which contains many previously studied lattices of R-module classes. The sublattice structure of p r R is studied in this paper and is related to ring and module properties of R
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