Abstract: The Kaczmarz algorithm is a method for solving linear systems of equations that was introduced in 1937. The algorithm is a powerful tool with many applications in signal processing and data science that has enjoyed a resurgence of interest in recent years. We'll discuss some of the history of the Kaczmarz algorithm as well as describ...

Creator:

Weber, Eric (Iowa State University)

Created:

2022-04-26

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

If A is a finite-dimensional algebra with automorphism group G, then varieties of generating r-tuples of elements in A, considered up to G-action, produce a sequence of varieties B(r) approximating the classifying space BG. I will explain how this construction generalizes certain well-known examples such as Grassmannians and configuration spaces...

Creator:

Williams, Ben (University of British Columbia)

Created:

2022-08-05

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

The Milnor–Moore theorem identifies a large class of Hopf algebras as enveloping algebras of the Lie algebras of their primitives. If we broaden our definition of a Hopf algebra to that of a braided Hopf algebra, much of this structure theory falls apart. The most obvious reason is that the primitives in a braided Hopf algebra no longer form a L...

Creator:

Westerland, Craig (University of Minnesota, Twin Cities)

Created:

2022-08-01

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

Topological Azumaya algebras are topological shadows of more complicated algebraic Azumaya algebras defined over, for example, schemes. Tensor product is a well-defined operation on topological Azumaya algebras. Hence given a topological Azumaya algebra $\mathcal{A}$ of degree $mn$, where $m$ and $n$ are positive integers, it is a natural questi...

Creator:

Arcila-Maya, Niny (Duke University)

Created:

2022-08-03

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

In order to incorporate ideas from algebraic topology in concrete contexts such as topological data analysis and topological lattice field theories, one needs effective constructions of concepts defined only abstractly or axiomatically. In this talk, I will discuss such constructions for certain invariants derived from the cup product on the coh...

Creator:

Medina-Mardones, Anibal (Max Planck Institute for Mathematics)

Created:

2022-08-02

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

I will talk about equivariant homotopy theory and its role in the proof of the Segal conjecture and the Kervaire invariant one problem. Then, I will talk about chromatic homotopy theory and its role in studying the stable homotopy groups of spheres. These newly established techniques allow one to use equivariant machinery to attack chromatic com...

Creator:

Shi, XiaoLin (Danny) (University of Chicago)

Created:

2022-08-04

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

I will share some reminiscences of my many years working with Gunnar. The career that I have had would not have been possible without his kindness, wisdom, and generosity.

Creator:

de Silva, Vin (Pomona College)

Created:

2022-08-04

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

The Gromov-Hausdorff distance between two metric spaces is an important tool in geometry, but it is difficult to compute. For example, the Gromov-Hausdorff distance between unit spheres of different dimensions is unknown in nearly all cases. I will introduce recent work by Lim, Mémoli, and Smith that finds the exact Gromov-Hausdorff distances be...

Creator:

Adams, Henry (Colorado State University)

Created:

2022-08-04

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

Configuration spaces of disks in a region of the plane vary according to the radius of the disks, and their topological invariants such as homology also vary. Realizing a given homology class means coordinating the motion of several disks, and if there is not enough space for the disks to move, the homology class vanishes. We explore how cluster...

Creator:

Alpert, Hannah (Auburn University)

Created:

2022-08-01

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

We develop a theory of limits for sequences of dense abstract simplicial complexes, where a sequence is considered convergent if its homomorphism densities converge. The limiting objects are represented by stacks of measurable [0,1]-valued functions on unit cubes of increasing dimension, each corresponding to a dimension of the abstract simplici...

Creator:

Segarra, Santiago (Rice University)

Created:

2022-08-01

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

A well-known and very useful result in algebraic topology is the statement that the Euler characteristic of G/N(T) in singular cohomology is 1, where G is a compact Lie group and N(T) is the normalizer of a maximal torus. In the presence of a transfer map as constructed by Becker and Gottlieb the above result shows that in any generalized cohomo...

Creator:

Joshua, Roy (The Ohio State University)

Created:

2022-08-02

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

Mathematics students learn a powerful technique for proving theorems about an arbitrary natural number: the principle of mathematical induction. This talk introduces a closely related proof technique called "path induction," which can be thought of as an expression of Leibniz's "indiscernibility of identicals": if x and y are identified, then th...

Creator:

Riehl, Emily (Johns Hopkins University)

Created:

2022-08-03

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

Cohomological ideas have recently been injected into persistent homology and have for example been used for accelerating the calculation of persistence diagrams by softwares, such as Ripser. The cup product operation which is available at cohomology level gives rise to a graded ring structure that extends the usual vector space structure and is ...

Creator:

Zhou, Ling (The Ohio State University)

Created:

2022-08-02

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

Persistent homology is a main tool in topological data analysis. So it is natural to ask how strong this quantifier is and how much information is lost. There are many ways to ask this question. Here we will concentrate on the case of level set filtrations on simplicial sets. Already the example of a triangle yields a rich structure with the Möb...

Creator:

Tillmann, Ulrike (University of Oxford)

Created:

2022-08-03

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

I will review the theory of ramification in number theory and then show that being totally ramified or unramified is equivalent to a natural condition in higher algebra. This leads to a much simplified calculation of THH of a ring of integers in a number field, relying on ramified descent (a kind of weaker etale descent).

Creator:

Berman, John (University of Massachusetts)

Created:

2022-08-03

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

Federated machine learning (FL) is gaining a lot of traction across research communities and industries. FL allows machine learning (ML) model training without sharing data across different parties, thus natively supporting data privacy. However, designing and executing FL jobs is not an easy task today. Flame is an open-source project that aims...

Creator:

Le, Myungjin (Cisco)

Created:

2022-04-29

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

I would like to talk about the interaction of traditional algebraic topology and homotopy theory with applied topology, and specifically describe specifically some opportunities for better integration of "higher tech" techniques into applications.

Creator:

Carlsson, Gunnar (Stanford University)

Created:

2022-08-05

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

To understand the function of neurons, as well as other types of cells in the brain, it is essential to analyze their shape. Perhaps unsurprisingly, topology provides us with tools ideally suited to performing such an analysis. In this talk I will present a selection of the results of a long-standing collaboration with Lida Kanari of the Blue Br...

Creator:

Kathryn Hess-Bellwald, Kathryn (École Polytechnique Fédérale de Lausanne (EPFL))

Created:

2022-08-01

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.

In this talk I will give an overview of two related projects. The first project concerns the high-degree rational cohomology of the special linear group of a number ring R. Church--Farb--Putman conjectured that, when R is the integers, these cohomology groups vanish in a range close to the virtual cohomological dimension. The groups SL_n(R) sati...

Creator:

Wilson, Jenny (University of Michigan)

Created:

2022-08-03

Contributed By:

University of Minnesota, Institute for Mathematics and its Applications.