###### Corona update

All physical activity is suspended until further notice, due to Covid19. Some activites may take place virtually, please be in touch with organisers.

### Recent Events

• Online Special seminar: The Day after COVID-19 Lockdown May 12, 15:10—16:00, 2020.

Speaker: Shai Shalev-Shwartz (CS- HUJI)

Title: The Day after COVID-19 Lockdown

Abstract: Given the latest statistics, we predict that with a proper differential social distancing placing different guidelines on the low-risk group compared to the high-risk group one could maintain a working economy without quarantine and save a factor of 5 on mortality while not flooding the health system. The talk will highlight some of the computational tools used to reach these conclusions.

Based on joint work with Amnon Shashua

Here are some relevant articles:

https://medium.com/@amnon.shashua/the-day-after-covid-19-lockdown-need-to-focus-on-the-vulnerable-42c0a360a27

https://medium.com/@amnon.shashua/the-path-for-economic-revival-4d60d652b381

https://medium.com/amnon-shashua/can-we-contain-covid-19-without-locking-down-the-economy-2a134a71873f

• Special Lecture Feb 27, 12:00—13:00, 2020.

Speaker: Yves de Cornulier (CNRS, University Lyon 1)

Place: Room -101, Math building (58)

Title: near actions

Abstract A near permutation of a set $X$ is a permutations “up to finite subset”. It can be formally defined as the germ at infinity of a homeomorphism of the one-point compactification of $X$. A near action of a group is a homomorphism into the group of near permutations of a set. We notably study realizability of near actions, namely understanding obstructions to being induced by a genuine action. These concepts can be applied to the study of the class $(M)$ of maximal abelian subgroups of $S_\omega/fin$, where $S_\omega$ is the group of permutations of the countable set $\omega$ and $fin$ is its normal subgroup of finitely supported permutations. Uncountable groups in the class $(M)$ have been studied by Shelah and Steprans (2007). We characterize countable abelian groups that occur in the class $(M)$.

• 2020 המדרשה המתמטית השנייה בנגב(*) Feb 24, 10:00—Feb 26, 16:00, 2020, שדה בוקר.

המדרשה היא כנס מתמטי המיועד לתלמידי מתמטיקה משנה ג’ והלאה, והיא תכלול ארבע סדרות של הרצאות על ידי חברי סגל מהמחלקה למתמטיקה באוניברסיטת בן-גוריון בנגב. זוהי הזדמנות להכיר חוקרים פעילים במתמטיקה, לשמוע הרצאות על תחום מחקרם באווירה ידידותית, לשוחח עימם ולשאול שאלות על מחקר מתמטי.

• Derived Categories Feb 15—16, 2020, Charles University in Prague.

A conference in celebration of the 60th Birthday of Amnon Yekutieli (Ben Gurion University) and the publication of his new book Derived Categories

• The HUJI-BGU Workshop in Arithmetic Jan 13, 10:30—16:15, 2020.

10.30 - 11.00 Welcome

11.00 - 11:50 Francesco Saettone (BGU), Analytic continuation of L-functions of characters: Tate’s thesis.

12.05 - 12.55 Zev Rosengarten (HUJI), L-functions of characters and regulators: Beilinson’s conjecture.

14.15 - 15.05 Amnon Besser (BGU), The p-adic Beilinson conjectures for number fields.

15.20 -16.00 Yotam Svoray (BGU), Polylogarithms and their geometry.

16.00 -16.15 (bonus content): Ishai Dan-Cohen (BGU) Regulators are polylogarithms.

All talks in room -101.

Some older events may be found on the pages of the Center for Advanced Studies.

### Past Events

(Star) marks events partly supported by the Center for Advanced Studies in Mathematics at Ben-Gurion University