October 2021
Public Access Category: All |
6:30pm» Jean Fasel, Université de Grenoble I, Grenoble, France- Time:
- 6:30pm
- Description:
- Speaker: Jean Fasel, Université de Grenoble I, Grenoble, France
Date/Time: 1 October 2021, 6:30pm IST/ 1:00pm GMT / 9:00am EDT (joining
time 6:15pm IST)
Zoom link:
https://univ-grenoble-alpes-fr.zoom.us/j/99339034373?pwd=MlIybEJYWjVSQnlqS1NWSDRpSk5wUT09
Title: Cohomotopy groups in algebraic geometry and unimodular rows
Abstract: We will discuss the notion of cohomotopy groups in algebraic
geometry. Our main example and motivation will be the study of unimodular
rows, but we will also discuss other examples such as unimodular m x n
matrices and Euler class groups. The general context of this study is
motivic homotopy theory, but we will avoid technicalities and motivate the
constructions using classical topology.
For more information and links to previous seminars, visit the website of
VCAS: https://sites.google.com/view/virtual-comm-algebra-seminar
- Time:
- 5:30pm
- Description:
- Speaker: Krishna Hanumanthu, Chennai Mathematical Institute, Chennai, India.
Date/Time: 8 October 2021, 5:30pm IST/ 12:00pm GMT / 8:00am EDT (joining
time 5:15pm IST).
Gmeet link: meet.google.com/gir-ohpw-ymu
Title: Seshadri constants.
Abstract: Seshadri constants of line bundles on projective varieties were
defined by J-P. Demailly in 1990, motivated by an ampleness criterion of
C. S. Seshadri. They are a measure of local positivity of line bundles
and have interesting connections to different areas in mathematics. We
will discuss some important questions that drive research on Seshadri
constants. We will also discuss their relationship with Waldschmidt
constants which are invariants attached to homogeneous ideals in
polynomial rings.
For more information and links to previous seminars, visit the website of
VCAS: https://sites.google.com/view/virtual-comm-algebra-seminar
- Time:
- 7:30pm
- Description:
- Speaker: Josh Pollitz, University of Utah, Salt Lake City, UT, USA.
Date/Time: 29 October 2021, 7:30pm IST/ 2:00pm GMT / 10:00am ET (joining
time 7:15pm IST).
Gmeet link: meet.google.com/iop-sgzk-nko
Title: Symmetries in Bass and Betti sequences over a complete intersection
ring .
Abstract: Despite homological algebra over a complete intersection ring
being unbounded, resolutions enjoy polynomial growth. That is to say, for
a finitely generated module over a complete intersection ring, its
sequence of Bass numbers and its sequence Betti numbers are eventually
given by quasi-polynomials with period two; the leading terms of the
quasi-polynomials are independent of the parity. In this talk, I will
discuss joint worth with Briggs and McCormick where we show the leading
terms of the two quasi-polynomials agree. The main tool is a higher order
support theory which generalizes the well-studied support varieties of a
complete intersection ring.
For more information and links to previous seminars, visit the website of
VCAS: https://sites.google.com/view/virtual-comm-algebra-seminar