Mathematical Sciences: Isogenies and Operations in Complex Oriented Cohomology

研究了许多椭圆曲线的模问题，如给定点为指定精确阶的椭圆曲线的分类问题。在一维形式群的背景下，可以研究类似但更复杂的问题。所得到的代数对象在代数拓扑中也以广义上同调环的形式出现。特别地，有限域上形式群变形的子群和等同构理论与Morava k理论和高交换性环谱的完备E(n)上同调密切相关。博士后尼尔·斯特里克兰（Neil Strickland）的目标是证明一些猜想，使这种联系更加精确。这项研究是代数拓扑的一部分，代数拓扑研究高维形状的某些特征，例如它们有多少孔，孔如何连接在一起或相互缠绕等等。这些问题是有意义的，即使物理空间只有三个维度。例如，如果一个量依赖于其他七个量，那么可以想象在抽象的八维空间中绘制函数关系图。研究这个图的性质是可能的和有用的，即使它不能在物理上实现。因为很难想象这样一个空间，所以把它的问题转化为代数问题是很有帮助的。一般来说，有两种转换方法，适用于不同类型的问题。在几何学中，基本的代数运算是测量距离和角度。在拓扑学中，有人可能会说，基本操作是计算孔洞（尽管在六维物体中精确地说明三维孔洞的含义并不容易）。这门学科的一个有趣的特点是，某些拓扑问题以一种意想不到的方式引发了代数问题，这些问题以前在数学中似乎不相关的领域得到了解决，比如数论。当前的项目旨在澄清这种现象的一个相当壮观的例子，并扩展相关的代数知识，以便涵盖更广泛的拓扑情况。＊＊＊

9401550 Miller A number of moduli problems for elliptic curves have been studied, such as that of classifying elliptic curves with a given point of specified exact order. Analogous but more intricate problems can be studied in the context of one-dimensional formal groups. The resulting algebraic objects also arise as generalized cohomology rings in algebraic topology. In particular, the theory of subgroups and isogenies of deformations of formal groups over a finite field is closely connected with the Morava K-theory and completed E(n) cohomology of ring spectra with higher commutativity properties. Neil Strickland, the postdoctoral associate, aims to prove a number of conjectures making this connection more precise. This research is part of algebraic topology, which studies certain features of higher dimensional shapes, such as how many holes they have, how the holes are linked together or twisted around each other and so on. These problems are meaningful even though physical space has only three dimensions. For example, if one quantity depends on seven others, then one can imagine drawing a graph of the functional relationship in an abstract eight-dimensional space. It is possible and useful to study the properties of this graph, even though it cannot be realized physically. Because it is so hard to visualize such a space, it is helpful to convert questions about it into algebraic problems. Broadly speaking, there are two methods of conversion, appropriate to different types of questions. In geometry, the basic algebraic operation is to measure distances and angles. In topology, one might say that the basic operation is to count holes (although it is not so easy to say what precisely is meant by a three-dimensional hole in a six-dimensional object). An interesting feature of the subject is that certain topological questions give rise in an unexpected way to algebraic problems which have previously been addressed in apparently unrelated are as of mathematics, such as number theory. The current project aims to clarify one quite spectacular example of this phenomenon, and to extend the relevant algebraic knowledge so as to cover a wider family of topological situations. ***