The Amsterdam-Leiden Seminar is organized jointly by VU University Amsterdam and Leiden University.

The seminar (usually) takes place once per month on Wednesday afternoon.

For more information, please contact the organizers: Rob van der Vorst (VU) and Vivi Rottschäfer (LU)

A database of earlier years' seminars (including the former VU-UvA dynamical analysis seminar) can be found here.

And a route description can be found here.

## Upcoming talks in 2019

Wednesday, **27 February**, 15:00-17:00

15:00-15:45: **Oliver Fabert
**

*Title:* Pseudo-holomorphic curve methods for Hamiltonian PDE

Coffee Break

16:15-17:00: **Sonja Hohloch
**

*Title:* TBA

## Previous talks in 2018

Wednesday, **21 November**, 15:00-17:00, WN-P656 **@VU Amsterdam**

15:00-15:45 **Onno van Gaans (LU)
**

*Title:***Partially ordered vector spaces by means of embedding**

*Abstract:* Many of the familiar function spaces used in analysis are naturally equipped with a vector space structure and a norm or topology. If we consider real valued functions, these spaces also have a natural partial order, which leads to the notion of a partially ordered vector space. The general theory of partially ordered vector spaces is poor. For vector lattices, which are partially ordered vector spaces in which every set of two elements has a least upper bound, a much richer theory is available. Since the 1990s an approach has been developed of studying partially ordered vector spaces by means of embedding in vector lattices. This approach turns out to be fruitful for spaces that allow an ``order dense'' embedding in a vector lattice. Such spaces are called pre-Riesz spaces. An overview of the theory of pre-Riesz spaces will be given with a focus on the notion of disjointness. Some recent results on disjointness preserving operators will be mentioned as well.

Coffee break

16:15-17:00 **Magnus Botnan (VU)
**

*Title:***Ge****ometry and topology in neural data**

*Abstract:* Understanding what drives neuronal activity is an active of research. For example, it is well-known that the activity level of a place cell in a rodent is a function of the rodent's spatial position as well as its head direction. However, there are most certainly other, possibly unknown, driving forces. In this talk I will discuss a recent framework, based on algebraic topology, to uncover topological properties of a-priori unknown covariates. This is joint work with Gard Spreemann, Benjamin Dunn and Nils Baas.