## 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

Tuesday, November 5, 2019 — 2:00 PM EST

**Luke MacLean, Department of Pure Mathematics, University of Waterloo**

"Reverse Mathematics"

We say that $S \subseteq \mathcal{P}(\omega)$ is an $\omega$-model of a subsystem of second order arithmetic if the $L_2$ structure $(\omega, S, +, \cdot, 0, 1, <)$ correctly models the subsystem in question. The goal of this lecture will be to prove that there is an $\omega$-model of $WKL_0$ consisting entirely of low sets.

This will involve learning about PA degrees and the low basis theorem.

All are welcome.

MC 5413

Tuesday, November 5, 2019 — 2:30 PM EST

**Andrej Vukovic, Department of Pure Mathematics, University of Waterloo**

We continue where last week's discussion left off by discussing the classification of semivaluations in the valuative tree. Then we return to our study of plane polynomial dynamics.

M3 3103

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