Title: The behavior of rational points in one-parameter families
Abstract: How often does a "random" algebraic plane curve f(x,y) = 0
have a solution with rational coordinates? In one-parameter "twist"
families of elliptic curves, Goldfeld conjectured that there should be
a rational point exactly half of the time. Recent progress towards
this conjecture makes use of Selmer groups, and I'll explain the
geometric idea underlying their construction. I'll also describe
results for families of curves of higher genus, and abelian varieties
Title: Stability patterns in representation theory and applications
Many natural sequences of objects come equipped with group actions, e.g. the symmetric group on n letters acting on a space X_n. This leads to fundamental instability of invariants, such as homology, arising from the representation theory of the sequence of groups. Representation stability is a new and increasingly important set of ideas that describe a sense in which such sequence of representations (of different groups) stabilizes.
Title: Inp-minimal ordered groups.
Abstract. The main goal of the talk is to present the proof of the theorem stating that inp-minimal (left)-ordered groups are abelian. This generalizes a previous result of P. Simon for bi-ordered inp-minimal groups.
The existence of sharply 2-transitive groups without regular normal subgroup was a longstanding open problem. Recently constructions have been given, at least in certain characteristics. We will survey the current state of the art and explain some constructions and their limitations. (joint work with E. Rips)
Title: Almost Congruence Extension Property for subgroups of free groups.
The talk essentially based on: https://arxiv.org/abs/1606.02345
Let G be a group and H
every normal subgroup N of H is an intersection of some normal subgroup of G with H. The CEP appears in group theory in different context.
The following question seems to be very difficult:
Which finitely generated subgroup of a free group has CEP?
Title: Old and New Results on Subgroup Growth in Pro-p Groups.
Abstract: I will survey our current knowledge about subgroup growth in pro-p growth. In particular I will present new solutions to long standing open problems in the area:
1. What is the minimal subgroup growth of non-$p$-adic analytic pro-$p$ groups? (Joint work with Benjamin Klopsch and Jan-Christoph Schlage-Puchta.)
2. What are the subgroup growths of the Grigorchuk group and the Gupta-Sidki groups? (Joint work with Jan-Christoph Schlage-Puchta.)