8 research outputs found

    On the number of transversals in latin squares

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    The logarithm of the maximum number of transversals over all latin squares of order nn is greater than n6(lnn+O(1))\frac{n}{6}(\ln n+ O(1))

    On the number of transversals in a class of Latin squares

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    Denote by Apk\mathcal{A}_p^k the Latin square of order n=pkn=p^k formed by the Cayley table of the additive group (Zpk,+)(\mathbb{Z}_p^k,+), where pp is an odd prime and kk is a positive integer. It is shown that for each pp there exists Q>0Q>0 such that for all sufficiently large kk, the number of transversals in Apk\mathcal{A}_p^k exceeds (nQ)np(p1)(nQ)^{\frac{n}{p(p-1)}}

    Additive triples of bijections, or the toroidal semiqueens problem

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    We prove an asymptotic for the number of additive triples of bijections {1,,n}Z/nZ\{1,\dots,n\}\to\mathbb{Z}/n\mathbb{Z}, that is, the number of pairs of bijections π1,π2 ⁣:{1,,n}Z/nZ\pi_1,\pi_2\colon \{1,\dots,n\}\to\mathbb{Z}/n\mathbb{Z} such that the pointwise sum π1+π2\pi_1+\pi_2 is also a bijection. This problem is equivalent to counting the number of orthomorphisms or complete mappings of Z/nZ\mathbb{Z}/n\mathbb{Z}, to counting the number of arrangements of nn mutually nonattacking semiqueens on an n×nn\times n toroidal chessboard, and to counting the number of transversals in a cyclic Latin square. The method of proof is a version of the Hardy--Littlewood circle method from analytic number theory, adapted to the group (Z/nZ)n(\mathbb{Z}/n\mathbb{Z})^n.Comment: 22 page
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