School of Mathematics

Starting with the "Leibniz" formula for π

 

π/4=1−1/3+1/5−1/7+…

 

the special values of Dirichlet L-functions have long been a source of fascination and frustration. From Euler's solution in 1734 of the Basel problem to Apery's proof in 1978 that zeta(3...

Cohen, Lenstra, and Martinet have given highly influential conjectures on the distribution of class groups of number fields, the finite abelian groups that control the factorization in number fields. Malle, using tabulation of class groups of number...

Two or infinity

Dan Cristofaro-Gardiner

It is conjectured that every Reeb flow on a closed three-manifold has either two, or infinitely many, simple periodic orbits. I will survey what is currently known about this conjecture. Then, I will try to explain some of the key ideas behind...