Geometry Seminar

Date: September 23, 2020

Time: 11:00AM - 12:00PM

Location: zoom

Speaker: Filip Rupniewski, IMPAN

Title: Cactus rank and identification of secant inside cactus varieties

Abstract: Every secant variety is contained in the corresponding cactus variety. However, according to our knowledge, there is no explicit equation of the secant variety which does not vanish on the cactus variety. I will present an algorithm for deciding if a given point in the cactus variety belongs to the secant variety in some special cases. I will also show the theorem for calculating the cactus rank of forms divisible by a large power of a linear form which allowed us to design the mentioned algorithm. Based on a joint work with M. Gałązka and T. Mańdziuk.