Algebraic Geometry Seminar

Seminar information archive ~05/21Next seminarFuture seminars 05/22~

Date, time & place Friday 13:30 - 15:00 118Room #118 (Graduate School of Math. Sci. Bldg.)
Organizer(s) GONGYO Yoshinori, KAWAKAMI Tatsuro, ENOKIZONO Makoto

Future seminars

2025/05/23

13:30-15:00   Room #118 (Graduate School of Math. Sci. Bldg.)
Takuya Miyamoto (University of Tokyo)
Pathology of formal locally-trivial
deformations in positive characteristic
[ Abstract ]
An infinitesimal deformation of an algebraic variety X is called (formally) locally trivial if it is Zariski-locally isomorphic to the trivial deformation. The locally trivial deformation functor of X is the subfunctor of the usual deformation functor associated with X consisting of locally trivial deformations. In this talk, I will construct an explicit example that is an algebraic curve in positive characteristic whose locally trivial deformation functor does not satisfy Schlessinger’s first condition (H_1), in contrast to the complex/characteristic 0 case. In particular, this provides a negative answer to a question posed by H. Flenner and S. Kosarew. I will also mention recent progress on the structure of fibers of locally trivial deformation functors.