BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Johannes Walcher (Heidelberg University) DTSTART:20210514T080000Z DTEND:20210514T090000Z DTSTAMP:20260423T024533Z UID:CGP-MP/12 DESCRIPTION:Title: On the rationality of MUMs and 2-functions\nby Johannes Walcher (Heide lberg University) as part of IBS-CGP Mathematical Physics Seminar\n\n\nAbs tract\nPoints of maximal unipotent monodromy in Calabi-Yau moduli space pl ay a central role in mirror symmetry\, and also harbor some interesting ar ithmetic. In the classic examples\, suitable expansion coefficients of the (all-genus) prepotential (in polylogarithms) under the mirror map are int egers with an enumerative interpretation on the mirror manifold. This corr espondence should be expected to extend to periods relative to algebraic c ycles capturing the enumerative geometry relative to Lagrangian submanifol ds. This expectation is challenged\, however\, when the mixed degeneration is not defined over Q. After musing about compatibility with mirror symme try\, I will discuss two recent results that sharpen these questions furth er: The first is a theorem proven by Felipe Müller which states that the coefficients of rational 2-functions are necessarily contained in an abeli an number field. (As defined in the talk\, 2-functions are formal power se ries whose coefficients satisfy a natural Hodge theoretic supercongruence. ) The second are examples worked out in collaboration with Bönisch\, Klem m\, and van Straten\, of MUMs that are themselves not defined over Q.\n LOCATION:https://researchseminars.org/talk/CGP-MP/12/ END:VEVENT END:VCALENDAR