Costas cubes
| Autor: | Jedwab, Jonathan, Yen, Lily |
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| Rok vydání: | 2017 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | A Costas array is a permutation array for which the vectors joining pairs of $1$s are all distinct. We propose a new three-dimensional combinatorial object related to Costas arrays: an order $n$ Costas cube is an array $(d_{i,j,k})$ of size $n \times n \times n$ over $\mathbb{Z}_2$ for which each of the three projections of the array onto two dimensions, namely $(\sum_i d_{i,j,k})$ and $(\sum_j d_{i,j,k})$ and $(\sum_k d_{i,j,k})$, is an order $n$ Costas array. We determine all Costas cubes of order at most $29$, showing that Costas cubes exist for all these orders except $18$ and $19$ and that a significant proportion of the Costas arrays of certain orders occur as projections of Costas cubes. We then present constructions for four infinite families of Costas cubes. Comment: 12 pages, 1 figure. Theorem 11 introduces two further infinite families of Costas cubes |
| Databáze: | arXiv |
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