Michael Tait

mtait at cmu dot edu

Office: Wean Hall 7124

About Me

I am an NSF Postdoctoral Fellow in the Department of Mathematical Sciences at Carnegie Mellon University. I am mentored by Po-Shen Loh, and my previous advisors were Jacques Verstraete for my PhD and Sebi Cioaba for my MSc. My research is focused on extremal combinatorics broadly, mostly focused on topics in extremal and spectral graph theory, combinatorial number theory, and finite geometry. Generally speaking, I either use algebraic methods to prove combinatorial results or I use combinatorial methods to prove algebraic results. For more information on my research, see my papers (below), my CV, and my research statement. For information on my teaching philosophy, please see my teaching statement and teaching page. I am supported by NSF grant DMS-1606350.

Besides mathematics, I spend my time exercising, reading, cooking (and eating!), watching baseball, and playing ball sports (poorly). I grew up in Wilmington, Delaware and attended Concord High School where I participated in basketball, wrestling, cross-country, track and field, and math league. I then ran collegiate track for 4 years and am a University of Delaware record holder in the outdoor 4x800m relay (7:32.89) and the indoor Distance Medley Relay (9:50.12). After that, while in grad school, I competed (not very well) on the UCSD Cycling Team. Currently, I spend time hanging out with the Pittsburgh Hounds.

Upcoming Travel:

Joint Math Meetings (San Diego, January 10-13)

AMS Spring Central Sectional Meeting (Ohio State University, March 17-18)

AMS Spring Eastern Sectional Meeting (Northeastern University, April 21-22)

UC San Diego Combinatorics Seminar (May x)

Your seminar?? (I have some grant money for travel: if you are interested in the type of research I do, please invite me to come speak or work on a problem!)

Teaching

I am currently teaching 21-301: Combinatorics. Here is the course website; it will be regularly updated so please check it frequently. Lectures are 12:30-1:20 pm in Hamerschlag Hall B103. My office hours are Tuesday from 2-4 pm and by appointment. See my teaching page for previous courses taught and my teaching statement to see who I am as a teacher.

Research (categories are approximations!)

## Extremal graph theory

On Coupon Colorings of Graphs, Discrete Applied Mathematics 193 (2015) 94--101. Co-authored with Bob Chen, Jeong Han Kim, and Jacques Verstraete.Small dense subgraphs of polarity graphs and the extremal number for the 4-cycle. Australasian Journal of Combinatorics, Volume 63 (1), (2015), 107--114, with Craig Timmons.Increasing paths in edge-ordered graphs: the hypercube and random graphs. The Electronic Journal of Combinatorics, 23.2, P2.15, with Jessica De Silva, Theo Molla, Flo Pfender, and Troy Retter.Degree Ramsey numbers of even cycles, to appear in Discrete Mathematics.Induced Turán numbers, to appear in Combinatorics, Probability and Computing with Po-Shen Loh and Craig Timmons.Turán numbers for Berge-hypergraphs and related extremal problems. Submitted with Cory Palmer, Craig Timmons, and Adam Wagner.## Combinatorial number theory

Sidon sets and graphs without 4-cycles. Journal of Combinatorics, Volume 5, Number 2, 155--165 (2014). Co-authored with Craig Timmons.Orthogonal polarity graphs and Sidon sets. To appear in Journal of Graph Theory. Co-authored with Craig Timmons.On sets of integers with restrictions on their products, European Journal of Combinatorics 51 (2016) 268--274, with Jacques Verstraete.A Szemerédi-Trotter type theorem, sum-product estimates in finite quasifields, and related results, Journal of Combinatorial Theory, Series A, Volume 147 (2017), 55--74. With Thang Pham, Craig Timmons, and Le Anh Vinh.A structure theorem for bricks in extraspecial groups, to appear in Journal of Number Theory. With Thang Pham, Le Anh Vinh, and Rob Won.## Spectral graph theory

Degenerate Turán problems for hereditary properties. Submitted with Vlado Nikiforov and Craig Timmons.Spectral bounds for the k-independence number of a graph. To appear in Linear Algebra and its Applications, with Aida Abiad and Sebastian CioabaOn the distance spectra of graphs. Linear Algebra and its Applications, Volume 497, (2016), 66--87, with 11 authors.Proof of a conjecture of Graham and Lovász concerning unimodality of coefficients of the distance characteristic polynomial of a tree. Submitted with Ghodrat Aalipour, Aida Abiad, Zhanar Berikkyzy, Leslie Hogben, Franklin Kenter, and Jephian Lin.Characterizing graphs of maximum principal ratio. To appear in the Electronic Journal of Linear Algebra with Josh Tobin.Three conjectures in extremal spectral graph theory, Journal of Combinatorial Theory, Series B with Josh Tobin.The Colin de Verdiere Parameter, excluded minors, and the spectral radius, submitted.## Miscellaneous

More Counterexamples to the Alon-Saks-Seymour and Rank-Coloring Conjectures. Electronic Journal of Combinatorics, 18.1, P26 (2011), with Sebastian Cioaba.Variations on a theme of Graham and Pollak. Discrete Mathematics, Volume 313, Issue 5, 665--676 (2013). Co-authored with Sebastian Cioaba.On the chromatic number of the Erdős-Rényi orthogonal polarity graph. Electronic Journal of Combinatorics, P2.21, 1--19, (2015). With Sam Peng and Craig Timmons.Independent sets in polarity graphs. To appear in SIAM Journal on Discrete Math with Craig Timmons.On a problem of Neumann. Submitted.Maximal planar subgraphs of fixed girth in random graphs. Submitted with Manuel Fernández and Nicholas Sieger.## Theses

The Alon-Saks-Seymour and Rank-Coloring ConjecturesM. Sc. Thesis, University of Delaware, 2011.Connections between graph theory, additive combinatorics, and finite incidence geometryPh.D. Thesis, UC San Diego, 2016.## Selected Talks

- Degree Ramsey numbers
- Induced Turán numbers
- Four conjectures in extremal spectral graph theory
- Increasing paths in edge-ordered graphs
- Recent results on graphs coming from projective planes
- Sum-product estimates in finite quasifields
- Sets of integers with restrictions on their products
- Coupon colorings of graphs
- Generalizations of the Graham-Pollak Theorem
- The Alon-Saks-Seymour and Rank-Coloring Conjectures (M.Sc. Defense)

## Mathematicians with whom I have had the pleasure to work

Ghodratollah Aalipour, Aida Abiad, Zhanar Berikkyzy, Bob Chen, Sebi Cioaba, Jay Cummings, Jess De Silva, Manuel Fernández, Mike Ferrara, Wei Gao, Kristin Heysse, Leslie Hogben, Dan Johnston, Franklin Kenter, Jeong Han Kim, Jephian Lin, Sarah Loeb, Po-Shen Loh, Theo Molla, Vlado Nikiforov, Cory Palmer, Sam Peng, Flo Pfender, Thang Pham, Troy Retter, Alex Schulte, Nicholas Sieger, Heather Smith, Craig Timmons, Josh Tobin, Casey Tompkins, Jacques Verstraëte, Le Anh Vinh, Adam Wagner, Rob Won, Rodrigo Zhou.

Honorable mentions (no papers [yet!]): Boris Bukh, Steve Butler, Fan Chung, Asaf Ferber, Paul Horn, Felix Lazebnik, Humberto Naves, Sankeerth Rao, John Urschel, Alex Vardy, Jason Williford, Michael Young.