### Yu Tsumura

Ross Assistant Professor in Mathematics

at The Ohio State University

Office: Room 400 Math Tower

**Current Teaching (Autumn 2017)**

**Upcoming schedule**

### Education

- B.S. Mathematics, Tsukuba University, 2008.
- Ph.D. Mathematics, Purdue University, 2008-2015.

**Dissertation Advisor**

Professor Ralph Kaufmann

**Postdoc mentor**

Professor Thomas Kerler

### Research Interests

My research interests include

low-dimensional topology, fusion category, modular category, Hopf algebra, knot theory, knot homology, topological quantum field theory,

higher categorical TQFT, homotopy quantum field theory, mapping class group,

arithmetic properties of elliptic curves, primality test, and interactions between these fields.

### Publications

**Published Articles**

- Primality tests for $2^p \pm 2^{(p+1)/2}+1$ using elliptic curves, Proc. Amer. Math. Soc. 139 (2011), no. 8.
- A 2-categorical extension of the Reshetikhin-Turaev theory. J. Pure Appl. Algebra 219 (2015), no. 11, 4953–4997.

**Submitted Articles**

- On the finiteness of Carmichael numbers with Fermat factors and $L=2^{\alpha}P^2$, arXiv:1710.01321

### Honors, Awards, and Grants

- A valedictorian of Mathematics, Tsukuba University, 2008
- Kiyo Sakaguchi Fellowship, The Prudential Life Insurance Company of Japan 2008-2010
- The Gerald R. MacLane award, Purdue University, 2009
- Graduate School Summer Research Grants, Purdue University, 2011
- Graduate School Summer Research Grants, Purdue University, 2012
- Graduate School Summer Research Grants, Purdue University, 2013

### Student

**Undergraduate Student**

- Ziheng Xiao (Summer 16-)

### Invited talks

- Topology Seminar, University of Minnesota, "A 2-categorical extension of the Reshetikhin-Turaev theory", March 24, 2014
- AMS Sectional Meeting, Texas Tech University, "A 2-categorical TQFT extending the Reshetikhin-Turaev TQFT", April 11-13, 2014
- AMS Sectional Meeting at University of St. Thomas (Minneapolis Campus) "The dihedral type subcategory of a metaplectic category" 10/28-30/2016
- AMS Sectional Meeting at Indiana University, April 1-2, 2017 "The coend and the dihedral type subcategory of a metaplectic category"

**Other Talks**

- Student Colloquium, Purdue University, "Invariants of knots and 3-manifolds", April 11, 2012
- Topology Seminar, Purdue University, "A 3-2-1 topological quantum field theory extending the Reshetikhin-Turaev TQFT", April 18, 2013
- Student Colloquium, Purdue University, "Topological quantum field theories and the Khovanov homology", January 30, 2014
- Student TQFT seminar, Purdue University, "A 2-dimensional modular functor and a modular category", March 7, 2014
- Student TQFT seminar, Purdue University, "The operator invariant of ribbon graphs", March 14, 2014
- Student TQFT seminar, Purdue University, "A construction of the Reshetikhin-Turaev TQFT'', March 28, 2014
- Graduate Research Day, Purdue University, "A 2-categorical extension of the Reshetikhin-Turaev topological quantum field theory'', November 22, 2014 .
- Topology Seminar, The Ohio State University, "A 2-categorical extension of the Reshetikhin-Turaev topological quantum field theory" September 15, 2015
- Working Group Seminar, The Ohio State University, "Overview and the definition and examples of braided G-crossed categories" April 7, 2016
- Working Group Seminar, The Ohio State University, "Definition and examples of equivariantization" April 14, 2016
- Working Group Seminar, The Ohio State University, "De-equivariantization 1" April 21, 2016
- Working Group Seminar, The Ohio State University, "De-equivariantization 2" April 28, 2016

### Conferences and Summer Schools that I attended

- AMS Spring Central Sectional Meeting, Illinois University, March 27-29, 2009
- Graduate Student Topology Conference, Indiana University, March 31-April 1, 2012
- Noncommutative Geometry and Operator Algebras, Vanderbilt University, May 4-10, 2012
- Midwest Topology Seminar, Illinois University, February 23, 2013
- Graduate Student Topology & Geometry Conference, University of Notre Dame, April 6-7, 2013
- MSRI 2013 Summer School: Physics and Mathematics of Link Homology, Universit$'{e}$ de Montr$'{e}$al, June 24 - July 5, 2013
- West Coast Algebraic Topology Summer School: Topological Field Theories, University of British Columbia, July 7-12, 2014
- Advances in Quantum and Low-Dimensional Topology 2016, March 11-13, 2016
- Summer Workshop 2016 & Knotting Nagoya June 4-5, 2016
- Fall 2016 Midwest Topology Seminar at Purdue University, September 17-18, 2016

### Teaching

Purdue University (Teaching Assistant)

- MA 26100 Multivariate Calculus, Spring 2010
- MA 26200 Linear Algebra And Differential Equations, Fall 2010
- MA 16200 Plane Analytic Geometry And Calculus II, Spring 2011
- MA 15900 Precalculus, Fall 2011
- MA 15300 Algebra and Trigonometry, Fall 2013
- MA 15300 Algebra and Trigonometry, Spring 2014

The Ohio State University

- 2568 Linear Algebra, Autumn 2015
- 2568 Linear Algebra, Spring 2016 (I was one of the Fundamentals of Engineering for Honors (FEH) Program staff)
- 2568 Linear Algebra, Autumn 2016
- 6111R Abstract Algebra Recitation, Autumn 2016
- 2568 Linear Algebra, Spring 2017
- 6112R Abstract Algebra Recitation, Spring 2017
- 2568 Linear Algebra, Autumn 2017
- 6111R Abstract Algebra Recitation, Autumn 2017
- 2568 Linear Algebra, Spring 2018 (two sections)

### Grading

At Purdue University

- MA 265 Linear Algebra, Fall 2008
- MA 266 Ordinary Differential Equations Spring 2009
- MA 353 Linear Algebra II With Applications. Fall 2009
- MA 511 Applied Linear Algebra, Fall 2009
- MA 572 Introduction to algebraic topology, Spring 2012
- MA 266 Ordinary Differential Equations, Spring 2012
- MA 571 Elementary Topology, Fall 2012
- MA 341 Foundations of Analysis, Fall 2012
- MA 366 Ordinary Differential Equations, Spring 2013
- MA 450 Algebra - Honors, Fall 2014
- MA 562 Introduction To Differential Geometry And Topology, Fall 2014
- MA 385 Introduction To Logic, Spring 2015
- MA 460 Geometry, Spring 2015