arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0905.0489math.COmath.AC
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给定亏格的数值半群个数的改进界

Improved bounds on the number of numerical semigroups of a given genus

Sergi Elizalde

摘要:

改进了亏格G的数值半群的个数N_g的已知下界和上界。从一个已知的递归描述的树T的数值半群,我们分析了它的一些性质,并使用它们来构造近似的T生成树的节点标记的某些参数的半群。然后,我们将这些树的继承规则转化为生成函数的函数方程,并求解这些方程,以获得其边界。我们的一些边界涉及到斐波那契数,而其他的则表示为生成函数。给出了T中具有无穷多个后代的数值半群个数的上界。

英文摘要:

We improve the previously best known lower and upper bounds on the number n_g of numerical semigroups of genus g. Starting from a known recursive description of the tree T of numerical semigroups, we analyze some of its properties and use them to construct approximations of T by generating trees whose nodes are labeled by certain parameters of the semigroups. We then translate the succession rules of these trees into functional equations for the generating functions that enumerate their nodes, and solve these equations to obtain the bounds. Some of our bounds involve the Fibonacci numbers, and the others are expressed as generating functions. We also give upper bounds on the number of numerical semigroups having an infinite number of descendants in T.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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