Seminar in Real and Complex Geometry

Thursday, August 12, 2021, 16:00-17:30, online (via zoom)




Dmitry Kerner
(Ben-Gurion University)

Germs of maps, group actions and large modules inside group orbits


Abstract
             

A map (k^n,o)-> (k^p,o) with no critical point at the origin can be rectified to a linear map. Maps with critical points have rich structure and are studied up to the groups of right/left-right/contact equivalence. The group orbits are complicated and are traditionally studied via their tangent space. This transition is classically done by vector fields integration, thus binding the theory to the real/complex case. I will present the new approach to this subject. One studies the maps of germs of Noetherian schemes, in any characteristic. The corresponding groups of equivalence admit `good' tangent spaces. The submodules of the tangent spaces lead to submodules of the group orbits. This allows to bring these maps to `convenient' forms. For example, we get the (relative) finite determinacy, and accordingly the (relative) algebraization of maps/ideals/modules.