"Bounded-Confidence Opinion Models with Random-Time Interactions"

One of my papers came out in final form yesterday. Here are some details.

Title: Bounded-Confidence Opinion Models with Random-Time Interactions

Authors: Weiqi Chu and Mason A. Porter

Abstract: In models of opinion dynamics, agents interact with each other and can change their opinions as a result of those interactions. One type of opinion model is a bounded-confidence model (BCM), in which opinions take continuous values and interacting agents compromise their opinions with each other if their opinions are sufficiently similar. In studies of BCMs, researchers typically assume that interactions between agents occur at deterministic times. This assumption neglects an inherent element of randomness in social interactions, and it is desirable to account for it. In this paper, we study BCMs on networks and allow agents to interact at random times. To incorporate random-time interactions, we use renewal processes to determine social-interaction event times, which can follow arbitrary interevent-time distributions (ITDs). We establish connections between these random-time-interaction BCMs and deterministic-time-interaction BCMs. We analyze the quantitative impact of ITDs on the transient dynamics of BCMs and derive approximate governing equations for the time-dependent expectations of the BCM dynamics. We find that BCMs with Markovian ITDs have consistent statistical properties (in particular, they have the same expected time-dependent opinions) when the ITDs have the same mean but that the statistical properties of BCMs with non-Markovian ITDs depend on the type of ITD even when the ITDs have the same mean. We numerically examine the transient and steady-state dynamics of our BCMs with various ITDs on different networks, and we compare their expected order-parameter values and expected convergence times.

What Happens in Oxford Stays in Oxford

I'm off to visit Oxford (i.e., my old place) for a few days. It's always nice to come back and visit!

Carlos Beltrán and Andruw Jones Elected to Major League Baseball Hall of Fame

Carlos Beltrán and Andruw Jones have been elected to the Major League Baseball Hall of Fame. They join Jeff Kent (who was elected in December by an Era Committee) in the Hall's 2026 class.

Given the very weak candidate slate this year, many returning candidates gained a lot of votes. Chase Utley, Andy Pettitte, Félix Hernández, Bobby Abreu, and others made huge gains in votes. Félix's Hernández's one-year gain is the largest such gain since the Hall of Fame returned to annual voting in 1967. The baseball writers clearly are rethinking how to evaluate Hall of Fame pitchers in the modern era. Hopefully, pitchers like Kevin Brown and Johan Santana (who got almost no support from the baseball writers when they were on the ballot) will be considered at some point by an Era Committee.

Chase Utley got almost 60% of the vote, so he may even be elected in 2027, which is faster than I was thinking. I now think that a 2028 election for Utley is most likely, whereas previously I was thinking that it would take longer. Utley has the highest voe percentage among all candidates who will be on the ballot again next year. Cole Hamels, with just more than 23% of the vote, is the only new candidate who got the requisite minimum 5% to remain on the ballot next year.

See this website and especially this website for the annual Hall of Fame vote tracker, which I use to follow writers' ballots as they make them public. The sites have been very flaky this year, but they're really great when one is able to access them.

Update: Some ESPN pundits have discussed some implications from the results of this year's Hall of Fame voting.

Update: Here's a nice recap of the voting results by Jay Jaffe.

Update (1/22/26): Jay Jaffe has written his candidate-by-candidate breakdown for the results of this year's Hall of Fame cycle.

Update (1/26/26): Jay Jaffe has written his 5-year prognostication for upcoming Hall of Fame ballots.

Dodgers Sign Kyle Tucker to 4-Year Deal!

The Dodgers have struck again! We have signed top free agent Kyle Tucker to a 4-year deal. The Dodgers are the Evil Empire, and I love it!

It's important that this is a shorter-term contract, as Tucker is a bit too fragile to go beyond 4 years.

RIP Erik Bollt (1967–2025)

My collaborator Erik Bollt died suddenly and unexpectedly last Sunday (the 7th). Erik is a well-known applied mathematician, and he was especially in the applied dynamical-systems community. Erik and I wrote two papers together, including our paper on mathematically modeling cow synchronization.

You can read about Erik's research on his web page and his Google Scholar page.

There will be a memorial article at some point.

Jeff Kent Elected to Baseball Hall of Fame!

Second baseman Jeff Kent has been elected to the Major League Baseball Hall of Fame by the Era Committee (which is the current version of the Veterans Committee. I am pleased that Kent is finally in the Hall.

Carlos Delgado did surprisingly well in the voting, so it sounds like he'll eventually make the Hall of Fame. Notably, Dale Murphy and Don Mattingly did not get enough votes (despite the fact that the Powers That Be seem to want them to be selected), and I agree that they should not be elected. Finally, I hope that Gary Sheffield, Barry Bonds, and Roger Clemens eventually make the Hall of Fame, but I won't be holding my breath (especially for the latter two).

"Clustering-Induced Localization of Quantum Walks on Networks"

One of my papers came out in published form today. Here are some details.

Title: Clustering-Induced Localization of Quantum Walks on Networks

Authors: Lucas Böttcher and Mason A. Porter