# Weekly bulletin

## Week starting Monday 24 April 2017

### Monday 24 April - Computational Mathematics Seminar

Start time: 4pm
Location: John Dedman Building G35 (seminar room)
Presenter(s): Dirk Pflüger (Universität Stuttgart)
Abstract:

In our group, we have successfully used and improved adaptive sparse grids for a range of higher-dimensional applications. They range from exascale simulations of hot fusion plasmas via the mining of vast datasets to topology optimization and financial applications.

In this talk, we consider non-intrusive stochastic collocation for uncertainty quantification, as our applications require us to treat the underlying simulation code as a black box. We propose spatially adaptive sparse grids for both the estimation of the stochastic densities and the stochastic collocation.

With sparse grids, the numerical discretization is still possible in higher-dimensional settings, and the integrated sparse grid approach leads to fast and efficient algorithms and implementations. This allows us to start with data that is provided by measurements and to combine the estimated densities with the model function's surrogate without introducing additional sampling or approximation errors. Bayesian updating allows us to incorporate observations and to adaptively refine the surrogate based on the posterior. Efficient and scalable algorithms for the evaluation of the surrogate function are available, which can achieve close-to-peak performance even on hybrid hardware.

### Thursday 27 April - MSI Colloquium 2017

Start time: 4pm
Location: John Dedman Building 27, Room G35.
Presenter(s): Corey Jones (MSI, ANU)
Abstract:

The study of operator algebras was initiated by von Neumann to provide a context for the algebras of observables that arise in quantum mechanics.  Since their introduction, operator algebras have come to play a central role in many branches of mathematics and physics.  In this talk, we will explain how symmetries of inclusions of operator algebras can be described in the language of tensor categories, providing a link with quantum groups and topological quantum field theory.

### Friday 28 April

Start time: 11am
Location: John Dedman Building 27, Room G35.
Presenter(s): Shibing Chen (ANU)
Abstract:

In this seminar we will give lectures on the Monge-Ampere equation, a reference book is Figalli’s “Monge-Ampere equation and its applications”. All interested people are welcome.

### Friday 28 April - MSI Honours Seminar Series

Start time: 1pm
Location: John Dedman Building 27, Room G35
Presenter(s): Edmund Heng and Stephen Deng (MSI/ANU)
Abstract:

Algebraic objects are often abstract and intuitions have mostly came from experience. The Category of Affine Schemes over $K$, being anti-equivalent to the Category of $K-algebra$ provides us a way of looking at abstract algebraic objects - Algebras, as concrete Geometrical objects - Affine Schemes. Pushing the same idea a little bit further, we can similarly look into a more specific set of Geometrical objects - affine group schemes, which corresponds to the algebraic object - Hopf Algebra.

In this talk I'll first introduce the idea of an Affine scheme through the functorial point of view and show how continuing on this idea allows us to view a more specific type of Algebra - Hopf Algebras, as Geometrical objects too. To save time and since Sam had talked about Categories, I'll assume we all know what it is and skip defining it.

Updated:  28 April 2017/Responsible Officer:  Director/Page Contact:  School Manager