## Contact Info

Pure MathematicsUniversity of Waterloo

200 University Avenue West

Waterloo, Ontario, Canada

N2L 3G1

Departmental office: MC 5304

Phone: 519 888 4567 x33484

Fax: 519 725 0160

Email: puremath@uwaterloo.ca

**University COVID-19 update:** visit our Coronavirus Information website for more information.

Please note: The University of Waterloo is closed for all events until further notice.

Wednesday, April 18, 2018 — 10:00 AM EDT

**Jitendra Prakash, Department of Pure Mathematics, University of Waterloo**

"Factorisation problems in RKHS"

We introduce the problem of factorisation of a positive operator *P* as *P*=*UU** where *U* is upper triangular, and relate it to RKHS. We shall also discuss some generalisations of the classical Fejer-Riesz theorem.

MC 5403

Tuesday, April 17, 2018 — 10:00 AM EDT

**Jitendra Prakash, Department of Pure Mathematics, University of Waterloo**

"Nevanlinna-Pick Interpolation Problems"

Nevanlinna-Pick interpolation problem seeks a holomorphic function on the unit disk of norm at most one which interpolates two sets of points. This problem can be viewed as a question about the multiplier algebra of the Hardy space. We shall outline this operator-theoretic approach.

MC 5417

Monday, April 16, 2018 — 10:00 AM EDT

**Jitendra Prakash, Department of Pure Mathematics, University of Waterloo**

"Review of Reproducing Kernel Hilbert Spaces"

In this talk we shall review some of the basic results in the theory of reproducing kernel Hilbert spaces and their multiplier algebras.

MC 5403

Friday, April 13, 2018 — 2:00 PM EDT

**Ross Willard, Department of Pure Mathematics, University of Waterloo**

"Uncountable SIs in residually small varieties in a countable signature, part II"

Continuing the proof of "the theorem" of McKenzie and Shelah, I will prove some properties of pp-1-types in subdirectly irreducible algebras whose monolith is (0,1)-generated.

MC 5479

Tuesday, April 10, 2018 — 1:30 PM EDT

**Stan Xiao, University of Oxford**

"Binary quartic forms with vanishing J-invariant and the subvariety problem"

Monday, April 9, 2018 — 4:00 PM EDT

**Hanfeng Li, SUNY Buffalo**

"Mean dimension and von Neumann-Lueck rank"

Mean dimension is an invariant in topological dynamics, while von Neumann-Lueck rank is an invariant in L2-invariants theory, closely related to the L2-Betti numbers. Based on joint work with Bingbing Liang, I will discuss how these two invariants are related to each other.

MC 5501

Friday, April 6, 2018 — 2:30 PM EDT

**Mahya Ghandehari, University of Delaware**

"Characterizing the Sobolev wavefront set via continuous wavelet transforms"

Friday, April 6, 2018 — 2:30 PM EDT

**McKenzie Wang, McMaster University**

"Examples of Ancient Flows on Bundles"

I will report on joint work with Peng Lu on constructing ancient flows on a large class of compact bundles. These examples are of type I and include both collapsed and non-collapsed cases. In special cases, we can also describe the forwards limit of these ancient flow. As a bonus of this work, we also obtain examples of such ancient flows for pseudo-Riemannian metrics.

MC 5403

Friday, April 6, 2018 — 2:00 PM EDT

**Ross Willard, Department of Pure Mathematics, University of Waterloo**

"Uncountable SIs in residually small varieties in a countable signature"

Thursday, April 5, 2018 — 10:30 AM EDT

**Barbara Csima, Department of Pure Mathematics, University of Waterloo**

"Every $\Delta^0_2$ degree is a strong degree of categoricity"

We sketch the proof that every $\Delta^0_2$ degree is a strong degree of categoricity. This is joint work with Keng Meng Ng.

MC 5417

Wednesday, April 4, 2018 — 4:00 PM EDT

**Seda Albayrak, Department of Pure Mathematics, University of Waterloo**

"Finite Automata and Transcendence Theory"

Tuesday, April 3, 2018 — 3:00 PM EDT

**Farida Shahata, Department of Pure Mathematics, University of Waterloo**

"More projective geometry"

Projective schemes make a comeback! Following our previous discussion on closed immersions and closed subschemes, the next natural step is to study closed embeddings of projective schemes.

As for affine schemes, we will see that a surjection of graded rings induces a closed embedding of projective schemes. Conversely, every closed subscheme of a projective scheme arises from a graded ideal, hence, is projective itself.

Tuesday, April 3, 2018 — 1:30 PM EDT

**Jason Bell, Department of Pure Mathematics, University of Waterloo**

"Last talk of the seminar"

MC 5479

University of Waterloo

200 University Avenue West

Waterloo, Ontario, Canada

N2L 3G1

Departmental office: MC 5304

Phone: 519 888 4567 x33484

Fax: 519 725 0160

Email: puremath@uwaterloo.ca

University of Waterloo

University of Waterloo

43.471468

-80.544205

200 University Avenue West

Waterloo,
ON,
Canada
N2L 3G1