Frank den Hollander is a participant of the Probability and Statistics of Discrete Structures (PSDS) program at the Simons-Laufer Mathematical Science Institute (SLMath), Spring 2025. This blog is part 2 in a trilogy of blogs.
Shankar Bhamidi, Remco van der Hofstad and I are sharing a house at 2439 Virginia Street, Berkeley, California during the time we participate in the Probability and Statistics of Discrete Structures (PSDS) program. Shankar and Remco stay for almost 4 months, I stay for 3 months. It is fun to share the house, because we buy groceries together, have meals together, discuss mathematics, and make short trips over the weekend. Serte Donderwinkel called our place the “SLMath fraternity”, which makes perfect sense because sometimes we do indeed feel like 'students on the run.'
The PSDS program started on January 22, with an opening program followed by a workshop. This was an excellent opportunity to get to know all the participants, including those who take part in the parallel program on Extremal Combinatorics. At one point we had 2 full mornings of 5-minute pitches by everyone present, introducing themselves and explaining what they hoped to achieve at SLMath, both in terms of mathematics and of scientific contacts. A great start!
The program at SLMath is intense. After taking the shuttle up in the morning (SLMath is on top of a steep hill; only some dare to walk up), the day is filled with seminars, open problem sessions, crash lectures on a variety of different topics, workshop talks, and extended working sessions in groups, interlaced with tea/coffee and lunch on the porch. And after taking the shuttle down in the late afternoon, and going for a swim in the YMCA lap-pool, there is dinner and further discussions at SLMath fraternity. Never a dull moment!

From left to right: Frank den Hollander, Shankar Bhamidi and Remco van der Hofstad in "SL Frat" clothing
In Berkeley, I wanted to work on new challenges, 'out of the box' problems that I had never worked on before, in order to learn and further expand my horizon. While at SLMath, I got involved in five different projects. The start of each of these was tough but, now that I am close to returning home (on April 18), several of them are converging and I feel enriched.
Shankar, Remco and I made a few trips, one along Highway 1 when my wife Lucia was visiting. The Californian coastline is spectacular, with lots of wildlife to be spotted. We also went to San Francisco a few times, which has lots to offer as well. The BART trains run frequently (BART = Bay Area Rapid Transit) and get you around quickly. San Franciso is huge and there are many interesting quarters with beautiful museums and fine restaurants. From April 9 to 12 we go to Los Angeles, where we give invited lectures at the “LA Probability Forum”, together with Joost Jorritsma. Perhaps we can see some more wildlife along the way.

Shankar Bhamidi (left) and Remco van der Hofstad (right) in the “SLMath fraternity house”
Since we have a whole house at our disposition, we have invited many of our colleagues to come over and have dinner at our place, which has been fun. We also organised a party on February 9, for the super-bowl event on television (which is sort of crazy and can really only be properly grasped by Americans). On April 13, we are organising a potlatch party. So, until we leave, the show goes on!
The cover photo shows the superbowl party organized by Frank, Remco and Shankar at the “SLMath fraternity house”.