Dear Colleagues, As part of its celebrations of the World Logic Day 2025, the Association for Logic in India (ALI) <https://logicindia.org/> invites you to an online lecture by Prof. Shashi Mohan Srivastava. The lecture details are as below. Date and time: ============== Date: January 16, 2025 Time: 18:00 IST Zoom Meeting details: =================== Meeting link: https://us02web.zoom.us/j/84357712770?pwd=LYLWbkiNat5vll4stGyn6Vx34nvXIu.1 Meeting ID: 843 5771 2770 Passcode: wldcali25 Lecture details: ============= Speaker: Prof. Shashi Mohan Srivastava, IACS Kolkata and RKMVERI Belur, India Title: Recalling Vaught's conjecture Abstract: Vaught's conjecture states the following. The countable models of a countable first order theory, up to isomorphism, are either countably many or continuum many. This problem is still open, and it seems not much activity has been going on on it. Speaker Bio: Prof. Shashi Mohan Srivastava is an Emeritus Professor at the Statistics and Mathematics Unit, Indian Statistical Institute (ISI), Kolkata, India, which he joined in 1980. He is also a Visiting Professor at the Indian Association for the Cultivation of Science (IACS), Kolkata, and the Ramakrishna Mission Vivekananda Educational and Research Institute (RKMVERI) Belur, Kolkata. He graduated from ISI Kolkata in 1980 under the supervision of Prof. A. Maitra. He was a member of the Institute for Advanced Studies, Princeton, during the academic year 1979–1980. Prof. Srivastava's primary research interest lies in descriptive set theory. He is the recipient of the Indian National Science Academy medal for young scientists, and is the author of the books, A Course on Borel Sets and A Course on Mathematical Logic, both published by Springer. He is an enthusiastic teacher and has written several expository articles aimed at popularising mathematical logic and set theory in India. We look forward to seeing you at the lecture. ---