Non UBC
DSpace
Florence, Mathieu
2019-03-17T02:01:20Z
2018-09-17T11:06
Let $p$ be a prime number, and let $S$ be a scheme of characteristic $p>0$.
For any integer $n>1$, one can build the scheme of Witt vectors of length $n$ of $S$, denoted by $W_n(S)$. It is a natural thickening of characteristic $p^n$ of $S$.
Let us say "$W_n$-bundle" (or Witt vector bundle if $n$ is understood) for "vector bundle over $W_n(S)$".
In this talk, we consider the following Question.
Let $V$ be a vector bundle over $S$.
$Q(n,V)$: Does $V$ extend to a $W_n$-bundle
I will first give precise (hopefully elementary) definitions, and basic properties of Witt vector bundles. I will then show that the answer to question $Q$ is positive,
when $V$ is the tautological vector bundle of the projective space of a vector bundle, defined over an affine base. I will discuss counterexamples in the general setting -- in a Galois-theoretic way.
If time permits, I plan to discuss the main motivation for raising question $Q$: lifting Galois representations.
This is joint work, with Charles De Clercq and Giancarlo Lucchini Arteche.
https://circle.library.ubc.ca/rest/handle/2429/68819?expand=metadata
45.0
video/mp4
Author affiliation: Université Paris 6
Banff (Alta.)
10.14288/1.0377006
eng
Unreviewed
Vancouver : University of British Columbia Library
Banff International Research Station for Mathematical Innovation and Discovery
Attribution-NonCommercial-NoDerivatives 4.0 International
http://creativecommons.org/licenses/by-nc-nd/4.0/
Faculty
BIRS Workshop Lecture Videos (Banff, Alta)
Mathematics
Algebraic geometry
Group theory and generalizations
Lifting Witt vector bundles
Moving Image
http://hdl.handle.net/2429/68819