Buildings, elliptic curves, and the K(2)-local sphere

4维球面的拟椭圆上同调

Quasi-elliptic cohomology of 4-spheres

本文针对 Sati–Schreiber 提出的拟椭圆上同调，计算4维球面在与 M5 膜位置相关的有限迷向群作用下的拟椭圆上同调，以推进其作为等变第4上同伦逼近的研究。

Isogenies of supersingular elliptic curves over finite fields and operations in elliptic cohomology

We investigate stable operations in supersingular elliptic cohomology using isogenies of supersingular elliptic curves over finite fields. Our main results provide a framework in which we give a conceptually simple proof of an elliptic cohomology version of the Morava change of rings theorem and also gives models for explicit stable operations in terms of isogenies and morphisms in certain enlarged isogeny categories. We relate our work to that of G. Robert on the Hecke algebra structure of the ring of supersingular modular forms.