### Thomas Friedrich 1949 – 2018

Thomas Friedrich was a German mathematian working in differential geometry and global analysis. He passed away in February 2018. Thomas Friedrich contributed substantially to the development of Berlin mathematics, he was Editor-in-Chief of the journal Annals of Global Analysis and Geometry for more than three decades (and also one of the founding editors-in-chief), and in 2003 he received the … Continue reading "Thomas Friedrich 1949 – 2018"

### Operators of finite propagation

In the starting post of this series we considered infinite band matrices (with uniformly bounded entries) acting on infinite vectors and asked at the end the question how to determine whether a given matrix, which is not a band matrix, can be approximated by such. Today we provide the setup in order to answer this question properly in … Continue reading "Operators of finite propagation"

### Strong cosmic censorship conjecture

The cosmic censorship conjectures concern the singularities arising in general relativity. In May the QuantaMagazine published an article (link) about a potential disproof of a strong version of the cosmic censorship conjecture. This article is nicely written and I recommend everybody interested in general relativity reading it. The preprint the QuantaMagazine refers to is arXiv:1710.01722 … Continue reading "Strong cosmic censorship conjecture"

### News around the ICM 2018

The ICM 2018 is currently taking place in Rio de Janeiro. Here are the prize winners of the IMU prizes and of the K-theory foundation, and the new IMU Executive Committee. The Fields medallists 2018 are Caucher Birkar, Alessio Figalli, Peter Scholze, and Akshay Venkatesh. There are also many more prizes and medals that are … Continue reading "News around the ICM 2018"

### Contractible 3-manifolds and positive scalar curvature

It is known that $$\mathbb{R}^3$$ admits a complete metric of uniformly positive scalar curvature. In fact, for any closed manifold $$X$$ and any $$k \ge 3$$ the manifold $$X \times \mathbb{R}^k$$ admits a complete metric of uniformly positive scalar curvature by a result of Rosenberg and Stolz (link). Now there exist contractible, open 3-manifolds which are not … Continue reading "Contractible 3-manifolds and positive scalar curvature"

### Prizes, prizes, prizes

Several prizes have been awarded in the past few weeks to mathematicians. Kyoto Prize The Kyoto Prize 2018 in the category Basic Sciences was awarded to Masaki Kashiwara from the RIMS at Kyoto University. (announcement) The Kyoto Prize is awarded annually to “those who have contributed significantly to the scientific, cultural, and spiritual betterment of mankind” … Continue reading "Prizes, prizes, prizes"

### Peter Scholze a new director at MPI Bonn

Recall that in the first post of this series we claimed that there exists an infinite matrix $$T$$ which is in the closure (in operator norm) of the band matrices with uniformly bounded entries, but for which we have $$\|T^{(R)}\| \to \infty$$. Here \[T^{(R)}_{m,n} := \begin{cases} T_{m,n} & \text{ if } |m-n| \le R\\ 0 & … Continue reading "Equivariant band matrices and Fourier series"