Speaker: Xin Jin (Boston College)Title: Multiplicative universal centralizer: Bruhat stratification, cluster structure and applicationsAbstract: The universal centralizer of a complex reductive group plays an important role in geometric representation theory. Aside from the standard group scheme structure, it possesses a natural Bruhat decomposition (and consequently a ''parabolic induction" structure) that makes the geometry quite explicit, and has many applications.The multiplicative version of the universal centralizer possesses a similar feature but has much richer (and more complicated) algebraic geometric structures. I will talk about recent results on several geometric features of the multiplicative universal centralizer. These include (a complete description of) a natural Bruhat stratification and the cluster structure on it. I will also talk about several applications. This is based on joint work with Ben Webster.

Talk Title: A cellular basis for mapping behavioural structureAbstract: To flexibly adapt to new situations, our brains must understand the regularities in the world, as well as those in our own patterns of behaviour. A wealth of findings is beginning to reveal the algorithms that we use to map the outside world. However, the biological algorithms that map the complex structured behaviours that we compose to reach our goals remain unknown. Here we reveal a neuronal implementation of an algorithm for mapping abstract behavioural structure and transferring it to new scenarios. We trained mice on many tasks that shared a common structure (organizing a sequence of goals) but differed in the specific goal locations. The mice discovered the underlying task structure, enabling zero-shot inferences on the first trial of new tasks. The activity of most neurons in the medial frontal cortex tiled progress to goal, akin to how place cells map physical space. These ‘goal-progress cells’ generalized, stretching and compressing their tiling to accommodate different goal distances. By contrast, progress along the overall sequence of goals was not encoded explicitly. Instead, a subset of goal-progress cells was further tuned such that individual neurons fired with a fixed task lag from a particular behavioural step. Together, these cells acted as task-structured memory buffers, implementing an algorithm that instantaneously encoded the entire sequence of future behavioural steps, and whose dynamics automatically computed the appropriate action at each step. These dynamics mirrored the abstract task structure both on-task and during offline sleep. Our findings suggest that schemata of complex behavioural structures can be generated by sculpting progress-to-goal tuning into task-structured buffers of individual behavioural steps.Bio: Tim Behrens is a neuroscientist at Oxford and UCLWebinar Link: https://us02web.zoom.us/j/89002014229?pwd=bzZuZGh6cVhOSjJ6TlNZVHgrRnNaQT09Followed by a reception with food and drink in 3rd floor atrium

Want to get exercise toward the end of the day but don’t want to go outside? Join the tunnel walk for a 30-minute walk led by a volunteer through MIT’s famous tunnel system. This walk may include stairs/inclines. Wear comfortable shoes. Free.Location details: Meet in the lobby with the big mirror, right inside the Collier Memorial entrance to Stata. Location photo below.Tunnel Walk Leaders will have a white flag they will raise at the meeting spot for you to find them.Prize Drawing: Attend a walk and scan a QR code from the walk leaders to be entered into a drawing for a getfit tote bag at the end of the getfit challenge. The more walks you attend, the more entries you get. Winner will be drawn and notified at the end of April. Winner does not need to be a getfit participant.Disclaimer: Tunnel walks are led by volunteers. In the rare occasion when a volunteer isn’t able to make it, we will do our best to notify participants. In the event we are unable to notify participants and a walk leader does not show up, we encourage you to walk as much as you feel comfortable doing so. We recommend checking this calendar just before you head out! [As of Feb 12, this calendar is defaulting to the year 1899. Click "today" to be brought to the current month.]Getfit is a 12-week fitness challenge for the entire MIT community. These tunnel walks are open to the entire MIT community and you do not need to be a current getfit participant to join.

We have two Sign Language Study Breaks coming up, with free Cafe 472 pizza and activities for all skill levels! When #1: Wed, March 12th, 4:30-6:00pmWhen #2: Wed, March 19th, 4:30-6:00pmWhere: MIT building 4, room 4-145What: Sign language practice + Cafe 472 pizzaRSVP (encouraged): https://asl.mit.edu/asl-study-break-rsvp-march-2025/ Come to socialize, learn the ASL fingerspelling alphabet, practice some basic signs, play sign language games, and for more experienced signers, we can practice conversational skills. All MIT community members are welcome! An ASL interpreter will be provided. Please RSVP to notify us of any other accommodations needed.

Spring recruiting is here, and is your LinkedIn “recruiter ready”? Does your headline need some attention? Not sure what to put “about me”? Through this 60-minute workshop you will learn ways to make your LinkedIn profile an “all-star”.This CAPD event is open to MIT undergraduates, graduate students, postdocs, and alumni.