Title: Eisenstein congruences and Euler systems I & II Speaker: Eric Urban (Columbia Univ.) Time: 2019-3-14, 14:30-17:00 Place: N817 Abstract: It is now well-known since the work of Mazur-Wiles that one can find lower bound for the size of Selmer groups by studying ordinary Eisenstein congruences. On the other hand, upper bound have been mainly obtained thanks to the use of Euler systems constructed from special units (cyclotomic, elliptic or Siegel units) or Heegner points. In this talk, I will present a general and new construction of Euler systems using Eisenstein congruences. I will stress and give some details on the key aspects of the construction and as an example, I will explain how this method recovers the Euler system of cyclotomic units. Attachment: