## Special Speakers

### Graeme Wilkin (National University of Singapore)

__When__: 2017.02.21

__Title__: *The reverse Yang-Mills-Higgs flow in the neighbourhood of a critical
point*

__Abstract__: The Yang-Mills-Higgs flow was originally studied by Simpson in the context of constructing Hermitian-Einstein metrics on Higgs bundles. Methods of Donaldson and Simpson show that the Yang-Mills-Higgs flow resembles a nonlinear heat equation on the space of Hermitian metrics on the bundle and therefore the
downwards flow is well-behaved with respect to existence and uniqueness, and it also has nice smoothing properties. On the other hand, the reverse flow is ill-posed and therefore even existence of solutions is problematic.

In this talk I will describe a new method to construct long-time solutions to the reverse Yang-Mills-Higgs flow that converge to a given critical point. The methods naturally lead to an algebraic criterion for two critical points to be connected by a flow line and a geometric condition to distinguish between broken and unbroken flow lines in terms of secant varieties of the underlying curve. If time permits I will talk about work in progress to describe the compactification of the space of flow lines in terms of the geometry of secant varieties.

### Topology Day 2017 (2017.03.14)

## Topics

A comprehensive plan for the term can be found here:

__Plan__

### Overview of Spectra

__Speaker__: Agnès Beaudry (CU Boulder)__When__: 2017.01.17__Notes__

### Cohomology Theories and Brown Representability

__Speakers__: Sebastian Bozlee and Cherry Ng (CU Boulder)__When__: 2017.01.24

### Prespectra and Spectra

__Speakers__: Nikki Sanderson and Katharine Adamyk (CU Boulder)__When__: 2017.01.31

### The Stable Homotopy Category as a Triangulated Symmetric Monoidal Category

__Speaker__: Matthew Pierson (CU Boulder)__When__: 2017.02.07

### Vector Bundles and the Thom Isomorphism Theorem

__Speaker__: Jordan Watts (CU Boulder)__When__: 2017.02.14

### Thom Spectra and the Pontryagin-Thom Theorem

__Speaker__: Andy Riddle (CU Boulder)__When__: 2017.02.21

### Quillen's Theorem: MU and Formal Group Laws

__Speaker__: Cliff Blakestad (CU Boulder)__When__: 2017.02.28

### K-Theory

__Speaker__: Markus Pflaum (CU Boulder)__When__: 2017.03.07- Notes

### S-Modules

__Speaker__: Agnès Beaudry (CU Boulder)__When__: 2017.03.21

### Symmetric Spectra

__Speaker__: Paul Lessard (CU Boulder)__When__: 2017.04.11,18

### Infinity Categories

__Speaker__: Jonathan Wise (CU Boulder)__When__: 2017.04.25