arXivDaily arXiv每日学术速递 周一至周五更新
arXiv math/0009113math.NT
收藏

Apollonian圆填充:数论

Apollonian Circle Packings: Number Theory

R. L. Graham, J. C. Lagarias, C. L. Mallows, A. R. Wilks, C. H. Yan

摘要:

阿波罗圆填充是通过重复地用更多的相切圆填充相互相切的圆之间的空隙而产生的。在这样的填充中,每个圆都可能具有整数曲率半径,我们称这样的填充为{ \em积分阿波罗圆填充}。本文研究了这类填充中出现的整数曲率集的数论性质。填充中的四个相切圆的每个笛卡尔四元组给出{ \em笛卡尔方程}的整数解,该方程与四个相互相切的圆的曲率半径相关:$2 (x^2 + y^2 + z^2 + w^2) - (x + y + z + w)^2 = 0.$每个完整的阿波罗圆填充由满足笛卡尔方程的整数的某个{ \em根四元组}分类,并且对应于填充中出现的特定四元组圆。我们确定的根四倍体的大小低于$T$的数量的渐近。我们研究的整数出现在一个给定的整数包装,并确定同余限制,有时适用。最后,我们提出的证据表明,出现在一个完整的阿波罗圆包装的整数曲率半径的集合具有正密度,实际上代表了所有足够大的整数不排除的同余条件。在一系列的同伴论文“阿波罗圆填充:几何和群论”,我们调查了各种群论性质的这些配置,以及各种扩展到更高的维度和其他空间,如双曲空间。

英文摘要:

Apollonian circle packings arise by repeatedly filling the interstices between mutually tangent circles with further tangent circles. It is possible for every circle in such a packing to have integer radius of curvature, and we call such a packing an {\em integral Apollonian circle packing.} This paper studies number-theoretic properties of the set of integer curvatures appearing in such packings. Each Descartes quadruple of four tangent circles in the packing gives an integer solution to the {\em Descartes equation}, which relates the radii of curvature of four mutually tangent circles: $2 (x^2 + y^2 + z^2 + w^2) - (x + y + z + w)^2 = 0.$ Each integral Apollonian circle packing is classified by a certain {\em root quadruple} of integers that satisfies the Descartes equation, and that corresponds to a particular quadruple of circles appearing in the packing. We determine asymptotics for the number of root quadruples of size below $T$. We study which integers occur in a given integer packing, and determine congruence restrictions which sometimes apply. Finally, we present evidence suggesting that the set of integer radii of curvatures that appear in an integral Apollonian circle packing has positive density, and in fact represents all sufficiently large integers not excluded by congruence conditions. In a series of companion papersr ``Apollonian Circle Packings: Geometry and Group Theory,'' we investigate a variety of group-theoretic properties of these configurations, as well as various extensions to higher dimensions and other spaces, such as hyperbolic space.

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。

↑