# Past Events

### Sebastien Picard

UBCNon-Kahler Degenerations of Calabi-Yau Threefolds

October 4, 2024

ESB 2012 and Zoom

It was proposed in the works of Reid in the mathematics literature and Candelas-Green-Hubsch in the string theory literature to connect Calabi-Yau threefolds with different topologies by a process which degenerates 2-cycles and introduces new 3-cycles. This operation may connect a Kahler Calabi-... Read more

### Dror Bar Natan

University of TorontoThe Strongest Genuinely Computable Knot Invariant in 2024

October 4, 2024

UBC

"Gennuinely computable" means we have computed it for random knots with over 300 crossings. "Strongest" means it separates prime knots with up to 15 crossings better than the less-computable HOMFLY-PT and Khovanov homology taken together. And hey, it's also meaningful and fun.

Further... Read more

- Topology

### Federico Trinca

UBCUnstable minimal spheres in hyperkähler 4-manifolds with degree one Gauss lift

October 3, 2024

ESB 4133

Complex submanifolds of Kähler manifolds are prototypical examples of stable, minimal submanifolds of higher codimension. In 1990, Yau asked whether it was possible to classify stable minimal spheres in hyperkähler 4-manifolds, proposing that all stable minimal spheres are holomorphic for some... Read more

- Differential geometry
- Mathematical Physics
- Partial Differential Equations

### Sean Douglas

UBCExtensions To The Fractional Chain Rule

October 2, 2024

ESB 4133 (PIMS Library)

In this talk, we establish a fractional chain rule in the context of weighted Triebel-Lizorkin spaces. This result notably extends the fractional chain rule to weighted Sobolev spaces with an integrability index less than one. Additionally, we determine an explicit relationship between the... Read more

- Harmonic Analysis and Fractal Geometry

### Zachary Selk

Queen's UniversityStochastic Calculus for the Theta Process

October 2, 2024

The theta process is a stochastic process of number theoretical origin arising from a scaling limit of quadratic Weyl exponential sums. It shares many properties in common with the Brownian motion such as its Hölder continuity, covariance structure, quadratic variation, scaling properties and so... Read more

- Probability

### Dr. Leonila Lagunes

UCLAMath-Bio: Modeling reveals the strength of weak interactions in stacked ring assembly

October 2, 2024

ESB 4133

Cells employ large macromolecular machines for the execution and regulation of many vital processes for cell and organismal viability. Interestingly, cells cannot synthesize these machines as functioning units. Instead, cells synthesize the molecular parts that must then assemble into the... Read more

- Mathematical Biology

### Chris Ryan

UBC"Near" Weighted Utilitarian Characterizations of Pareto Optima

October 1, 2024

ESB 4133 (PIMS Library)

We characterize Pareto optimality via "near" weighted utilitarian welfare maximization. One characterization sequentially maximizes utilitarian welfare functions using a finite sequence of nonnegative and eventually positive welfare weights. The other maximizes a utilitarian welfare function... Read more

- Discrete mathematics

### Elina Robeva

UBCLearning causal models via algebraic constraints

September 27, 2024

ESB 2012 and Zoom

The main task of causal discovery is to learn direct causal relationships among observed random variables. These relationships are usually depicted via a directed graph whose vertices are the variables of interest and whose edges represent direct causal effects. In this talk we will discuss the... Read more

### Nicolas Dupré

Universität Duisburg-EssenHomotopy classes of simple pro-p Iwahori-Hecke modules

September 27, 2024

UBC

Let G be a p-adic reductive group and k a field of characteristic p. The category Rep(G) of smooth k-linear representations is at the heart of the mod-p Langlands program. If we let I be a pro-p Iwahori subgroup of G, there is an associated convolution algebra H=k[I\G/I], called the pro-p... Read more

- Number Theory

### Ido Levin

University of WashingtonHierarchy of geometrical frustration in elastic ribbons: theory and experiments

September 26, 2024

MATH 204 and Zoom

Residually stressed structures are common in nature across many scales, and they have become increasingly relevant in man-made materials. Recently, geometrical formulations of elasticity have elucidated that the rich physics of stressed structures — which results in shape transitions, symmetry... Read more