Our Faculty

Brendan W. Sullivan

Brendan W. Sullivan

Assistant Professor of Mathematics

Office Hours

Office: Cardinal Cushing Library, Room G-11 (basement)

Office hours: Open door policy; if my door is open, you're welcome to come in! No need to make appointments, just stop by.

Guaranteed times: Mondays, 2:45-5:15 p.m.; Wednesdays, 12:00-1:15 p.m.; Thursdays, 1:30-3:00 p.m. 


D.A., Mathematics, Carnegie Mellon University, 2013.
Dissertation: Textbook and Course Materials for 21-127 Concepts of Mathematics.
Advisors: Dr. Jack Schaeffer, Dr. John Mackey.

M.S., Mathematics, Carnegie Mellon University, 2010.

B.A., Mathematics & Physics, Hamilton College, 2007.


I grew up loving "math" because I was quick with numbers and computations. I studied physics and math in college, but grew to learn I really liked physics because of the math used therein. Along the way, I also realized that mathematics is not about counting and calculating, but rather about beautiful patterns, grappling with truth and uncertainty, and facing the wonders of the universe head-on in all their awesome glory. In grad school, I raced off to learn about more magical worlds of math and stuffed my brain full of knowledge but, through a combination of factors, discovered that I was much better at sorting through this knowledge and conveying it to others than I was at utilizing it for my own sake. That is to say, I wasn't quite suited for creative research, but teaching called out to me ardently and insistently.  Ever since, I've sought to reach out to every student I come across, to show them a glimmer of the beauty of math, and to show them that everyone truly is a "math person", whether they know it or not.

What I Love about Emmanuel:

I am still fairly new here but have already met so many more friendly, personable people than I could possibly count! Students, staff, and faculty alike: everyone has been supportive and helpful.

The environment within the Department of Mathematics is fantastic, as well. My colleagues are always willing to help out, share ideas, and create opportunities for each other. And the students are wonderful! I hope they can tell that my own passion for math and enthusiasm in class feeds off their own motivation and commitment. Every day in class is a new and exciting adventure with a great group of fellow intellectual explorers.

Courses I Teach

  • MATH1101 College Algebra
  • MATH 1105 Topics in Contemporary Math
  • MATH1112 Calculus II
  • MATH1121 Applied Math for Management
  • MATH 2103 Calculus III
  • MATH 2109 Discrete Methods
  • MATH 3113 Special Topics in Math
    (Intro to Combinatorics & Graph Theory)

I am running the Math Department's ongoing "Puzzle of the Week" contest. Follow the blog for updates: http://mathpotw.blogspot.com/
We post a new puzzle (almost) every week. You earn points for your submissions, and the top scorers at the end of the academic year win prizes!

I serve as the advisor to Emmanuel's chapter of the Pi Mu Epsilon Honor Society, as well as the student-run EC Math Club. Email me if you're interested in learning more about the club and joining our mailing list!

Publications + Presentations

I have constructed some mathematics-themed crossword puzzles for the MAA's Mathematics Magazine:

  • "What Do You Study?", Math. Mag. 86 (2013) 370-371 [pdf link]
  • "Types Theory", Math. Mag. 87 (2014) 186-197 [pdf link]
  • "Award Winners", Math. Mag. 87 (2014) 360-361,402 [pdf link]
  • "2D or not 2D", Math. Mag. 88 (2015) 52-54 [pdf link]
  • "Books for a Math Audience", Math. Mag. 88 (2015) 154-155 [pdf link]
  • More forthcoming! This is a regular gig with one puzzle per issue (5 times per year).

Recent publications:

  • "Dominos on a rectangular board", Math Problems 87 (2014) 299-302 [pdf link]

Past publications:

  • R. Bedient, M. Frame, K. Gross, J. Lanski, B. Sullivan, 2011: Higher Block IFS 2: Relations between IFS with different levels of memory. Fractals, 18, 399-408. [pdf link]
  • R. Bedient, M. Frame, K. Gross, J. Lanski, B. Sullivan, 2011: Higher Block IFS 1: Memory reduction and dimension computations. Fractals, 18, 145-155. [pdf link]
  • A.J. Silversmith, N.T.T. Nguyen, B.W. Sullivan, et al., 2008: Rare-earth ion distribution in sol-gel glasses co-doped with Al3+. Journal of Luminescence, 128, 931-933. [pdf link]

For my doctoral thesis, I wrote a textbook for a course that introduces students to mathematical proofs and problem-solving, entitled Everything You Always Wanted to Know about Mathematics (but didn't even know to ask): A Guided Journey into the World of Abstract Mathematics and the Writing of Proofs. Publication details forthcoming. I use this text in our course MATH2109 Discrete Methods, and it has been in use at Carnegie Mellon University for their course 21-127 Concepts of Mathematics for several years.

  • Hugh D. Young Graduate Student Teaching Award for 2013, Carnegie Mellon University (Mellon College of Science)

Research Focus

Current research: Pursuit-evasion games on graphs, especially Lazy Cops & Robbers.

  • Graph theory studies network connections. Think of Facebook, with nodes (called "vertices") representing each person and connections (called "edges") amongst the nodes representing who is friends with whom; in this sense, Facebook is a big graph.
  • "Cops & Robbers" is a game played on graphs. A team of Cops place themselves on the vertices of a given graph, and then the Robber places himself on a vertex. The two sides alternate turns: on their turn, the Cops get to move along the edges, then the Robber does the same, and they go back and forth like this. If a Cop lands on the Robber, he is caught and the Cops win. If the Robber is able to evade the Cops indefinitely, then he wins.
  • This game has been studied extensively since its introduction in the 1980s. Mathematicians have made great strides towards understanding what kinds of graphs allow one Cop to win, which graphs require more and how many are required, etc. However, there remain many open questions and unproven conjectures. This is a very active research area!
  • Since this is a game, this research can be purely recreational (as it is for me). But these results also have important applications and implications in computer science and programming. A good example is writing programs to search and organize large datasets efficiently.
  • "Lazy Cops & Robbers" is a variant of the game wherein, on the Cops' turn, only one of them is allowed to move. The main question becomes: Does this rule change the game significantly? For a given graph, do the same number of Cops suffice, or might we need more (and how many)?

I recently conducted a summer research project with two Emmanuel students. We investigated the Lazy Cops game on particular graphs, including graphs based on the movements of Chess pieces. We obtained several new and significant results and are currently working on publications to be submitted to scholarly journals. In addition, the two students (Niko Townsend & Mikayla Werzanski) will presented some of our results at the Young Mathematicians Conference at Ohio State University in Auguat 2015. Here is a link to the abstract for their presentation which summarizes our results.

Past research: In my undergrad and graduate careers, I worked on projects in a variety of math branches:

  • Fractals, specifically Iterated Functions Systems with memory. Suppose we have a set of transformations defined on the unit square. What if we disallow specific sequences of transformations? What sort of images result? Can such situations be reformulated by changing the set of transformations and removing the disallowance of certain sequences? This was investigated in previous publications: see links here and here. (This grew from a senior distinction project during my undergraduate years.)
  • Partial differential equations and the finite element method. I studied these topics in graduate school and am still interested in them.
  • Combinatorics and graph theory, specifically tiling problems and games on graphs (see, especially, "Cops & Robbers" above in Current research.)

Overall, I typically find myself interested in problems where several (perhaps seemingly unrelated) branches of mathematics collide.

I also maintain an active interest in the Basel Problem and the always-growing number of proofs of this centuries-old fact. I am compiling a list of all published proofs of this fact and have plans to write a book about them.

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