Thirteen talks at great probability departments


More photos on my flickr account

University of British Columbia


Edward Perkins and Martin Barlow were great hosts. I appreciate their input on duals and meteors over lunch. Cindy Greenwood escorted me to the talk and was very pleasant company. Her description of her emeritus research as uninhibited is intriguing. 

Anthony Quas made me feel very welcome. After traveling all day it was great to arrive to a luxurious room on the Victoria harbor. Under the advice of a cyclist I met at Caffe Fantastico, I took the long way to UVIC. The result -- an epic sunny bike ride up the coast. Over lunch I learned from the past chair, Christopher Bose, about the "math-guru" of UVIC. How I understand it, they brought in a young PhD and gave him the task of improving their calculus program. I hope U.S. institutions jump on this idea! An undergrad at the seminar told me that this was the first talk he had completely followed. I appreciate the compliment. Eric Foxall loaned me $1.25 for my ferry ride home and has since been loaning some nice ideas on non-backtracking coalescence. 

Lunch with Toby Johnson, Ken Alexander and James Zhao at Lemonade. According to Toby it is the future of fast food. With ready-made dishes like "faro, calamari, hawaiian hearts of palm, shitake" I see where he's 
coming from. I met many nice mathematicians, among them Richard Arratia. In the early 80's he proved site
recurrence for annihilating random walks on Z^d. I'm working on a similar process. It was a pleasant surprise 
to get to chat. Also, his musings on the new trend of quantity over quality was striking. I appreciated his many questions and comments throughout the premiere of "Splitting Hairs (with choice)."  Toby pointed out that probabilists should more judiciously use the word "model" when talking about the processes we study -- using it only when we actually model something.  Again, I see where he's coming from.

University of California Los Angeles


Upon arriving, I was quickly directed to Tom Liggett’s office. I admire his work and was lucky to get in a quick conversation. Apparently there are dual notions of duals: one graphical the other analytic. During the talk the
 audience was fantastic -- even borderline rowdy at times (a rare and precious occurrence at a seminar). Marek Biskup offered a clarifying heuristic for the smallest interval and corrected some erroneous pronunciations. The day concluded with a swim in UCLA’s 50m outdoor pool and a Persian dinner with grad student Ian Zemke. He just posted his first paper. Worth looking at for the diagrams alone. 

University of California San Diego


UCSD left a very favorable impression. The beautiful bike commute through Torrey Pines was a good start. And, it didn’t hurt to speak at a well-attended seminar; rather exciting to see Ron Getoor there. I would be remiss not to mention how neat Ruth Williams and Pat Fitzsimmons are. Todd Kemp outdid himself as host. He took me out for coffee then lunch, let me perform some card tricks and guided a campus photo-quest. His advice on undergrad research will change how I run my REU project this summer. For one, the undergrads I work with will get much more structure. Jason Schweinsberg spoke with me about non-spatial coalescence and donated an idea to a meteor model.

Stanford University


Tianyi Zheng was a friendly host. She took me to lunch and dinner and helped me find a nice photo. It is rather helpful to get to talk to a variety of postdocs.  Persi Diaconis gave a pithy opinion on my proposed undergrad research problem -- insisting that we shouldn't stray from the cutting edge with the research given to undergrads. I'm curious what balance I will strike between tangible success and serious research this summer. The seminar was a double header; I followed Takis Konstatopoulos. He warmed up the audience with a great talk about exchangeability. After my talk Persi said at first he was worried, but that I overcame his first impression. I'll take that as an especially nice compliment. Dinner at La Bodeguita del Medio with Tianyi, Takis, Eric Marberg and Evita Nestoridi was a lot of fun. Butcher paper tablecloths greatly facilitate conversations between mathematicians. 

University of California Davis


Davis has an astonishing cycling culture. Bike highways, complete with roundabouts, twist through campus. Erik Slivken found me a nuanced decaf pourover and exhibited some relaxed biking styles. His default seems to be one hand in pocket -- not something I'd advise for Seattle riding. We started work on a hunter-antelope problem and built up some decent intuition. Erik thinks an admirable quality in mathematicians is being positive about other's work. Agreed, it's easy to get caught up in the aesthetics of our specialties. Sliding blackboards added a dimension to my talk and Janko Gravner suggested a plausible way to add a dimension to the Kakutani process.

Portland State University


PSU is a cute campus tucked right in the downtown. Their math atrium (above) is the best communal-math space I've ever seen. A blast to have a non-probability audience at all different levels. Great questions throughout -- very cool to take everyone on a "random walk" through the frog model. Thanks to Derek Garton for being flexible with scheduling and for encouraging several undergrads to attend.

Oregon State University


A room conflict gave me time to warm the audience up with a magic trick. Sleight of hand always leaves me a little shaky, but I recovered quickly. Much thanks my host Yevgeniy Kovchegov. We had several conversations during my visit. Perhaps the most striking covered his umbrage over models fabricated just to use techniques in the author’s bag of tricks. I also appreciate his novel heuristic for the frog model and, unrelated, for suggesting the local CLT to make an estimate. Mina Ossiander spoke with me for some time about interval splitting and also the current state of OSU undergrad math. I think we have the same philosophy; it is helpful to distinguish between pure and applied. I ended with a visit to Ed Waymire. He shared a neat branching problem and mentioned a project motivated by bee nesting. Who knows, the "bee model" could be the next big thing. 

University of California Berkeley


I couldn't have asked for a better ending to this journeyAllan Sly weighed in on non-uniform path measures and pointed me to a neat result about perturbed lattices. My largest audience yet was a great mix of students and faculty (many slipped out before the photo). Always a pleasure to see Jonathon Hermon, a grad student with a frenetic stream of good ideas about the frog model. Coffee afterwards with David Aldous and his students was also quite enjoyable. In just ten hours I managed to occupy four different coffee shops (all of which suited my aesthetic), and squeeze in four fantastic meals. The last, and best, was with Alan Hammond, Riddhipratim Basu, Miki Rasz, and Michael Preishl. Alan was aware of the blog before my arrival. This added a sportive meta feeling to the visit. The night ended with a candid discussion about math culture. It was a nice way to decompress, mathematicians love meta conversations.

Indiana University

Russell Lyons went to great lengths to make my stay memorable. For one, he was attentive and discerning about my research. This is greatly appreciated. Also, we had several nice meals, Turkish, Tibetan and Afghani. The middle of which was with Elizabeth Houseworth, David Fisher and Nick Travers. David and I have similar taste in restaurants. Elizabeth and I share an interest in biological modeling, and chalkboard vacuums. Russ made me aware of a few great insider gems: the outdoor 50m pool, a nice local co-op and the limestone canyon at McCormick Creek Park. I enjoyed my conversation with Nick about frogs, cookies, meteors and our vague goals for proof techniques we’d like to someday use. Kevin Pilgrim and Corrin Clarkson are very engaged leaders of IU's vibrant, well-thought out undergrad program. I’m particularly interested in the Directed Reading Program. It pairs a grad student to mentor an undergrad’s reading project. This then culminates in an end of term presentation. I have tried several times to run something analogous at UW, and am inspired to keep trying. 

Purdue University

Jonathon Peterson and I spent most of our time wrangling with a frog model in a random environment. I met his student Sung Won Awn, who just posted his first paper in RWRE. The seminar was my best attended ever; a good mix of just-starting and experienced mathematicians. Purdue houses a variety of great thinkers. Mark Ward in statistics was enthusiastic about generating functions, and Harsha Honnappa from industrial engineering inquired about my work in random algorithms. He shared a nice choice-queueing theory problem. 

University of Pennsylvania

Philadelphia was a great end to this trip. Robin Pemantle shared some interesting problems, and gave a helpful reference for the undergraduate research I directed this summer. We also spent some time understanding a recent result about how many random permutations are needed to generate S_n (turns out to be four). Over a sashimi lunch I met his student Albert Chen, who is also interested in "choice" processes. The math culture at Penn is quite vibrant, it was neat to have attendees from neighboring Temple University and University of Delaware.