3
$\begingroup$

What is a good reference for the story of congruences such as

$$\displaystyle \tau(n) \equiv \sigma(11)(n) \mod\ 691$$

with a conceptual explanation with connections to étale cohomology, etc?

  • 1
    Brian Conrad was writing a book on this and it was available on his web site. However, the PDF link there seems not to work any more. If it has been published that would be a modern source complementing the Swinnerton-Dyer notes.2010-11-24
  • 1
    @T..: Dear T.., I don't believe that Brian's book has been published (so far).2010-11-26

2 Answers 2