Algebra / Number Theory / Combinatorics Seminar

Given a polynomial defined over a field $K$, you can build an extension of $K_\infty / K$ by adjoining inverse images of some point $\alpha \in K$. The behavior of these extensions (including the degree , ramification, and associated Galois representations) are surprisingly different in the cases that $K$ is a number field versus a […]

Kloosterman sums are explicit exponential sums which occur in several contexts in number theory and arithmetic geometry. Bessel functions encode a great deal of representation-theoretic information about finite groups of Lie type, but they are difficult to compute in general. In this talk, we will carefully define these objects and describe a direct relationship between […]

The unique minimal generating set for a semigroup of lattice points in an n-dimensional polyhedral cone is called its Hilbert basis. In the case when the cone is spanned by lattice points, this Hilbert basis is finite, however its cardinality can be much larger than n. Nevertheless, a conjecture of Sebö states that each point […]

Extremal graph theory asks how many edges a graph can have while avoiding a given substructure. We will begin with a brief, accessible introduction to this area, before turning to a natural variant, the bipartite Turan number $(m,n;H)$, which restricts the host graph to be bipartite. This setting is especially natural when $H$ itself is […]