Published on Department of Mathematics Calendar (https://calendar.math.yale.edu)

Home > Calendar > Calendar

Monday, March 30, 2026

  • « Prev [1]
  • Next » [2]
Time Items
All day
 
3pm
Existence of genus 2 minimal surfaces in 3-spheres [3]
03/30/2026 - 3:45pm

In the past decades, we have witnessed rapid development in the construction of minimal surfaces with controlled topology by Simon-Smith min-max theory. In this talk, I’ll discuss the existence of a number of genus 2 minimal surfaces in a 3-sphere with a positive-Ricci-curved metric. This is based on the recent work joint with Adrian Chu and Yangyang Li.

Location:
KT 906
 
4pm
Knot complements decomposing into prisms [4]
03/30/2026 - 4:00pm

The Menasco-Reid conjecture supposes a negative answer to the question: Is there a hyperbolic knot complement which contains a closed embedded totally geodesic surface? Another Kirby problem asks which hyperbolic knot complements admit hidden symmetries? Here a manifold $M$ admits hidden symmetries, if $M$ covers an orbifold $Q$ and  $Q$ is not the quotient of $M$ by symmetries. Historically, there were three knot complements known to have hidden symmetries, and a conjecture Neumann and Reid states these are the only such examples.  After giving some of the relevant background, we will construct examples of knot complements that are counterexamples to both conjectures. Each of these knot complements has the property that it admits a decomposition into geometric prisms.  This is joint work with Jason DeBlois and Arshia Gharazolou and has appeared on the arxiv: arXiv:2507.01263.

Location:
KT 203
 
Coulomb branches of 4d N=2 gauge theories and the double affine Grassmannian. [5]
03/30/2026 - 4:30pm
Coulomb branches of 3d N=4 gauge theories for a gauge group
G have been rigorously defined by Braverman, Finkelberg and Nakajima.
These are affine (singular) symplectic algebraic varieties; their
algebras of functions can be defined via the equivariant Borel-Moore
homology of certain ind-schemes closely related to the affine
Grassmannian of G.

The story is significantly more complicated in 4 dimensions. In that
case from physics one expects that the corresponding Coulomb branches
are (more or less) singular hyper-kahler manifolds, which look
drastically different in different complex structures: while for
generic complex structure it is still supposed to be an affine
algebraic variety, whose coordinate ring is just given by the
equivariant K-theory of the above ind-schemes, for some special
complex structure it is not; in that case the corresponding variety
has  a structure of an integrable system with affine base and with
generic fiber being an abelian variety (examples include the total
space of the affine Toda integrable system or the so-called Dolbeault
hyper-toric varieties).

In this talk I will
1) review the above ideas
2) present a conjectural construction of the homogeneous coordinate
ring of the above (projective over affine) varieties via the
Borel-Moore homology of some spaces related this time to the affine
Grassmannian of the affine Kac-Moody group associated to G
3) Explain how to make this construction precise in the case when G is a torus.

 
Location:
KT 801
 
Print Calendar [6]
Subscribe to calendar .ics feed [7]
Visit our web site at http://math.yale.edu for updates and special announcements

Links
[1] https://calendar.math.yale.edu/calendar/grid/day/2026-03-29 [2] https://calendar.math.yale.edu/calendar/grid/day/2026-03-31 [3] https://calendar.math.yale.edu/event/existence-genus-2-minimal-surfaces-3-spheres [4] https://calendar.math.yale.edu/event/knot-complements-decomposing-prisms [5] https://calendar.math.yale.edu/event/coulomb-branches-4d-n2-gauge-theories-and-double-affine-grassmannian [6] https://calendar.math.yale.edu/print/list/calendar/grid/day [7] webcal://calendar.math.yale.edu/calendar/export.ics