Repeats every week every Sunday until Sat Feb 01 2020 except Sun Oct 27 2019.
11:00am to 1:00pm
Location:
Ross 70
Elon Lindenstrauss "Arithmetic applications of diagonal flows"
I will give an introduction to the dynamics of higher rank diagonal flows on homogeneous spaces,
including both the rigidity theorems of such flows and their applications to orbits of arithmetic interest,
in particular CM points and integer points on spheres.
I hope to cover parts of the following papers:
Einsiedler, Manfred ; Lindenstrauss, Elon ; Michel, Philippe ; Venkatesh, Akshay . The distribution of closed geodesics
Repeats every week every Sunday until Sat Feb 01 2020 except Sun Oct 27 2019.
4:00pm to 6:00pm
Location:
Ross 70
Tomer Schlank "Prismatic cohomology" (after Bhatt and Scholze)
Abstract: We shall discuss (Weil) cohomology theories for algebraic varieties.
When working with schemes over p-complete rings and taking cohomologies with p-complete coefficients one gets a plurality of such cohomology theories (e'tale, De-Rahm, Crystalline, etc.. ). The comparison between these different cohomology theories is a subtle subject known as "p-adic hodge theory" .
In joint work with K. Zhang we construct some explicit canonical geometries on various classes of complex manifolds, following a general symmetry principle pioneered by Calabi in the 70's. Our focus is to allow edge type singularities (that are the natural higher-dimensional analogues of conical Riemann surfaces studied by Picard and others since the 19th century) and study Gromov-Hausdorff limits as the angle in the cone tends to zero.
Title: Extending the Spectral Radius to Finite-Dimensional Power-Associative Algebras
Abstract: The purpose of this talk is to introduce a new concept, the \textit{radius} of elements in arbitrary finite-dimensional power-associative algebras over the field of real or complex numbers. It is an extension of the well known notion of the spectral radius.
As examples, we shall discuss this new radius in the setting of matrix algebras, where it indeed reduces to the spectral radius, and then in the Cayley-Dickson algebras, where it is something quite different.
Manchester Building (Hall 2), Hebrew University Jerusalem
Title:
The symplectic topologist as a dynamicist
Abstract:
The deveolpment of symplectic topology was motivated by Hamiltonian mechanics. It has been particularly successful in addressing one specific aspect, namely fixed points and periodic points of discrete-time Hamiltonian systems. I will explain how such applications work, both in older and more recent examples.
