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Luke MacLean, Department of Pure Mathematics, University of Waterloo

"Coding isomorphisms without using relations (part 2)"

A grand introduction to computability theory will be given so that in part 3 we can answer the questions posed in part 1.

MC 5403

Spencer Whitehead, Department of Pure Mathematics, University of Waterloo

"Clifford Algebras and Dirac Operators"

Talk #1 (9:30-10:30): Spiro Karigiannis, Department of Pure Mathematics, University of Waterloo 

Title: Calibrated subbundles of R^7, part II
Abstract: I will continue, and hopefully conclude, the discussion of calibrated subbundles in R^7. We will quickly review the previous talk and then focus on the coassociative case, which corresponds to negative superminimal surfaces.

Benoit Charbonneau and Spencer Whitehead, Department of Pure Mathematics, University of Waterloo

"Zometool workshop"

Hanging from the rafters of M3 is a Zometool construction of a projection of the 120-cell: one of five exceptional convex regular polytopes, and the four-dimensional analogue of the dodecahedron. This seminar is a hands-on learning activity, where participants have the chance to construct a Zometool 120-cell, as well as other projections of four-dimensional geometric constructions as time permits. 

Luke MacLean, Department of Pure Mathematics, University of Waterloo

"Coding isomorphisms without using relations"

Michael Albanese, UQAM

"The Yamabe Invariant of Non-Kähler Surfaces"

The Yamabe invariant is a real-valued diffeomorphism invariant coming from Riemannian geometry. Using Seiberg-Witten theory, LeBrun showed that the sign of the Yamabe invariant of a Kähler surface is determined by its Kodaira dimension. We consider the extent to which this remains true when the Kähler hypothesis is removed.

This seminar will be held jointly online and in person:

Shengda Hu, Wilfrid Laurier University

"Riemannian metrics and generalized geometry"

We will discuss some computations involving Riemannian metrics in the context of generalized geometry. We will try to illustrate various constructions involving metric connections and their curvatures.

MC 5403

Spiro Karigiannis, Department of Pure Mathematics, University of Waterloo

"Calibrated subbundles of $\mathbb R^7$"

Xuanlong Fu, University of Toronto

"Tracial  oscillation zero and stable rank one"

Let A be a separable (not necessarily unital) simple C*-algebra with strict comparison. We show that if A has tracial approximate oscillation zero then A has stable rank one and the canonical map \Gamma from the Cuntz semigroup of A to the corresponding lower-semicontinuous affine function space is surjective. The converse also holds.

Jesse Madnick, National Taiwan University

"Associative 3-folds in Squashed 7-Spheres"