Number theory learning seminar 2016-2017
The seminar will meet
Wednesdays 1:30--3:30pm in Room 384H.
This year's seminar will focus on etale cohomology, the goal being
to understand Laumon's proof of the main theorem of Deligne's Weil II paper that gave
a powerful and vast generalization of the Riemann Hypothesis over
finite fields. Familiarity with various basic
topics in arithmetic geometry (schemes, class field theory, derived categories, etc.)
whenever needed to get through a lecture in finite time.
In the fall we will largely focus on understanding key examples and calculations
as well as proofs of serious theorems concerning etale sheaf theory, aiming to get through much of Chapter 1 of the book of
Freitag and Kiehl. That will get us through the important smooth and proper base change theorems,
as well as the basic formalism of l-adic cohomology. In the winter we will delve
further into the cohomology theory (especially to duality theorems and
Kunneth formulas), and then move on to Laumon's technique of l-adic Fourier transforms
in the sheaf setting.
Here are some references relevant to this year's seminar (in approximate order of appearance):
Some notes that Conrad wrote long ago that we will be following as the template
for the fall and winter (supplemented by other references for omitted details indicated therein); this is an edited .pdf
file, explaining some occasional (irrelevant) blank spaces in the middle of text
[FK] "Etale Cohomology and the Weil Conjectures" by Freitag and Kiehl
[Mi] "Etale Cohomology" by Milne
[KW] "Weil Conjectures, Perverse Sheaves, and l-adic Fourer transform" by Kiehl and Weissauer
[M1] "Analytic etale duality" (preprint) and [M2] "q-crystalline cohomologies" (in preparation)
by Masullo
Notes -- use at your own risk.
These are
informal notes. They may change without warning.
Fall quarter
1
Oct. 5
Conrad
Overview (main goals and etale morphisms)
.pdf
2
Oct. 12
Conrad
Smooth maps, etale topology/sheaves, sheaf operations, stalks
.pdf
3
Oct. 19
Rosengarten
Constructibility, fundamental group, henselian rings, and applications (1.1.7, 1.2.1-1.2.5)
.pdf
4
Oct 26
Sherman
First calculations: Zariski comparison, Kummer/Artin-Schreier sequences, cohomology
of curves (1.2.6-1.2.7, [9])
.pdf
5
Nov. 2
Warner
Cohomology and limits, and reduction of proper base change to constant coefficients
(1.3.1-1.3.4.2, [9])
6
Nov. 9
Venkatesh
Artin approximation and proof of proper base change (1.3.4.2, [3])
.pdf
7, 8
Nov. 16, 30
Landesman
Smooth base change, local acyclicity, and vanishing cycles (1.3.5, [6])
.pdf
9
Dec. 14
Masullo
Formal GAGA (EGA III)
Winter quarter
10
Jan. 18
Tam
Cohomology with proper supports and Ehresmann's theorem
(1.3.6-1.3.7, omit proof of 1.3.6.4)
.pdf
11
Jan. 25
Zavyalov
Relative purity (section 10 of [9], 7.4.5 of [2] for slicker method)
12, 13
Feb. 1, 8
Feng
Poincare duality (1.3.8, [26])
14
Feb. 15
Silliman
Kunneth formula and Artin comparison (1.3.9-1.3.10, [9], [2])
15
Feb. 22
Devadas
Basic adic formalism (1.4.1-1.4.4.6)
.pdf
16
March 1
Lawrence
Advanced adic formalism (1.4.4.7-1.4.6)
.pdf
17
March 8
Raksit
Adic Artin comparison (1.4.7-1.4.8)
.pdf
March 15
Cancelled
Arizona Winter School
18
March 22
Ronchetti
Sheaf Frobenius, Lefschetz trace formula, and purity (1.5)
.pdf
Spring quarter
19
April 12
Lim, Dore
Weil sheaves and weights [KW, I.1-I.2.11]
.pdf
20
April 19
Feng
Proof of Lefschetz trace formula [FK, II, 2-4]
.pdf
21
April 26
Kemeny
Convergence radius and determinant weights [KW, I.2.12-I.3.2]
22
May 3, 10
Rosengarten
Monodromy and real sheaves [KW, I.3.3-I.4]
.pdf
May 17
Cancelled
Scheduling conflict
23
May 24
Venkatesh
l-adic Fourier transform [KW, I.5] with examples
.pdf
May 31
Masullo
Analytic duality and de Rham cohomologies [M1], [M2]
24
June 7
Sherman, Tam
Weil conjectures [KW, I.6-I.7]
.pdf