Localglobal principles for representations of quadratic forms
Abstract
We prove the localglobal principle holds for the problem of representations of quadratic forms by quadratic forms, in codimension $\geq 7$. The proof uses the ergodic theory of $p$adic groups, together with a fairly general observation on the structure of orbits of an arithmetic group acting on integral points of a variety.
 Publication:

Inventiones Mathematicae
 Pub Date:
 November 2007
 DOI:
 10.1007/s0022200700777
 arXiv:
 arXiv:math/0604232
 Bibcode:
 2007InMat.171..257E
 Keywords:

 Mathematics  Number Theory
 EPrint:
 TeX clash causing O to appear as \emptyset fixed