We had our last meeting of the CUNY Class Field Theory Student Learning Seminar on Wednesday May 8, 2024.
We achieved our goal of reading through and presenting the material in the book A Gentle Course in Local Class Field Theory by Pierre Guillot.
In the Fall 2024 semester, this seminar was replaced by the CUNY Number Theory Student Seminar.
The main goal of the seminar will be for graduate students to read, learn and present the material in the book A Gentle Course in Local Class Field Theory by Pierre Guillot. Graduate students will take turns presenting sections of the book and solve exercises contained at the end of each chapter.
This book offers a self-contained exposition of local class field theory. The only prerequisite is a first semester of Galois theory. It is written for beginning graduate students. The book is split into four parts:
Part I: Preliminaries
Part II: Brauer Groups
Part III: Galois Cohomology
Part IV: Class Field Theory
This material is useful for a variety of disciplines, including number theory, representation theory, algebraic geometry, and algebraic topology.
Any graduate student at the CUNY Graduate Center is welcome and encouraged to participate in this seminar! Professors are also welcome to attend but the intended audience for this seminar is graduate students.
This seminar is organized by Ajmain Yamin.
You can contact me at ayamin(at)gradcenter(dot)cuny(dot)edu.
There will be weekly meetings on Wednesdays at 4:15 PM - 6:15 PM.
The meetings will be at the Graduate Center, Math Thesis Room (4214.03).
Participants may also join the meetings virtually through zoom. Send an email to ayamin(at)gradcenter(dot)cuny(dot)edu for the permanent zoom link.
Speaker: Ajmain Yamin
Title: First Meeting
Meeting agenda: We will figure out how we intend to run this seminar. We may finish up some exercises from Part I of the book or move on to Part II Brauer groups: Chapter 5 on Skewfields, algebras, and modules.
Speaker: Connor Stewart
Title: Modules and endomorphisms
Meeting agenda: Connor will continue presenting Chapter 5: Skewfields, algebras, and modules. Last time Connor presented most of Section 1: Skewfields and algebras. This time, Connor will begin presenting Section 2: Modules and endomorphisms and move on to Section 3: Semisimplicity if there is time.
Speaker: Ajmain Yamin
Title: The radical and matrix algebras
Meeting agenda: Connor will finish presenting Section 3: Semisimplicity and Ajmain will pick up by presenting Section 4: The radical and Section 5: Matrix algebras.
Speaker: Ajmain Yamin
Title: The radical and matrix algebras
Meeting agenda: Ajmain will continue presenting Section 4: The radical and Section 5: Matrix algebras.
Speaker: Ajmain Yamin
Title: Matrix algebras
Meeting agenda: Ajmain will finish presenting Section 5: Matrix algebras.
Speaker: N/A
Title: N/A
Meeting agenda: There will be no meeting this week as there will be the Lightning Talks on Wednesday March 9th 4-6pm in the Math Lounge.
Speaker: Ajmain Yamin
Title: Review of Chapter 5 - Skewfields, algebras, and modules
Meeting agenda: Ajmain will give a brief review of Chapter 5 - Skewfields, algebras, and modules which will be recorded. After this, we will begin discussing exercises from Chapter 5.
Speaker: N/A
Title: Chapter 5 exercises
Meeting agenda: We will spend two meetings discussing exercises from Chapter 5.
Speaker: Ajith Nair
Title: Central simple algebras
Meeting agenda: Ajith will begin presenting Chapter 6 - Central simple algebras.
Speaker: Ajith Nair
Title: Tensor products and the group law
Meeting agenda: There was no meeting on April 20, as it was Spring break. On April 27, Ajith will finish his presentation on Section 2: Tensor products and perhaps cover Section 3: The group law, if there is time. This will be the last meeting of the Spring 2022 semester.
The first meeting will be on Wednesday June 22 9 AM- 11 AM Eastern Time.
The meetings will be held virtually through zoom
Send an email to ayamin(at)gradcenter(dot)cuny(dot)edu for the permanent zoom link.
Speaker: Connor Stewart
Title: The fundamental theorems
Meeting agenda: Connor will begin presenting the rest of Chapter 6: Central Simple Algebras starting with Section 4: The fundamental theorems.
Speaker: Connor Stewart
Title: Splitting fields and Separability
Meeting agenda: Connor will finish presenting Chapter 6: Central Simple Algebras by presenting Section 5: Splitting fields and Section 6: Separability. Connor will also start presenting Chapter 7: Combinatorial constructions Section 1: Introduction.
Speaker: Ajmain Yamin
Title: Group extensions and First applications: cyclic groups
Meeting agenda: Ajmain presented Chapter 7: Combinatorial Constructions Section 2: Group extensions and Section 3: First applications: cyclic groups.
Speaker: Ajith Nair
Title: Crossed product algebras
Meeting agenda: Ajith presented Chapter 7: Combinatorial Constructions Section 4: Crossed product algebras.
Speaker: Ajith Nair
Title: Compatibilities
Meeting agenda: Ajith started presenting Section 5: Compatibilities.
There will be weekly meetings on Wednesdays at 12:00 PM - 1:45 PM.
The meetings will be at the Graduate Center, Math Thesis Room (4214.03).
Depending on interest, we may stream the talks through zoom. Email ayamin(at)gradcenter(dot)cuny(dot)edu if you are interested in participating in the seminar but cannot attend in-person.
Speaker: Ajmain Yamin
Title: First meeting - Galois Cohomology
Meeting agenda: Ajmain will initiate new participants to the seminar. I will go over goals and objectives for CUNY CFT Student Learning Seminar. We will draft a schedule of talks for the Fall 2022 semester. Please attend this meeting if you are curious about attending/participating in the seminar. In the Fall semester, we will be starting Part III of Pierre Guillot's book, which is on Galois Cohomology. The main focus of this seminar will be to present the majority of the four chapters which constitute Part III:
Chapter 9: Ext and Tor
Chapter 10: Group cohomology
Chapter 11: Hilbert 90
Chapter 12: Finer structure
Please note: you do not need to have participated in previous semesters of the CUNY CFT Student Learning Seminar to follow along in this semester! Part III of Guillot's book is almost entirely independent from the previous sections of the book.
Speaker: Susan Rutter
Title: Complexes and The Ext groups
Meeting agenda: Last week Ajmain covered Section 1: Preliminaries and Section 2: Resolutions of Chapter 9: Ext and Tor. This week, Susan will begin presenting Section 3: Complexes and Section 4: The Ext groups.
Speaker: Valera Sergeev
Title: Long exact sequences and The Tor Groups
Meeting agenda: Valera will be presenting the remaining sections of Chapter 9: Ext and Tor, namely Section 5: Long exact sequences and Section 6: The Tor groups.
Speaker: None
Title: Exercises from Chapter 9: Ext and Tor
Meeting agenda: This meeting will be a problem solving session for the exercises in Chapter 9: Ext and Tor.
Speaker: Ajith Nair
Title: Definition of group (co)homology and The standard resolution
Meeting agenda: Ajith began presenting Chapter 10: Group cohomology, Section 1: Definition of group (co)homology and Section 2: The standard resolution.
Speaker: Ajith Nair and Connor Stewart
Title: The standard resolution, Low degrees, and Profinite groups and Galois cohomology
Meeting agenda: Ajith will finish presenting Chapter 10: Group cohomology, Section 2: The standard resolution and Connor will begin presenting Section 3: Low degrees and Section 4: Profinite groups and Galois cohomology.
Speaker: Connor Stewart
Title: Low degrees, Profinite groups and Galois cohomology
Meeting agenda: Connor will finish up the presentation of Chapter 10: Group cohomology, Section 3: Low degrees and Section 4: Profinite groups and Galois cohomology.
Speaker: Ajmain Yamin
Title: Kummer theory, Hilbert 90 in Galois cohomology and More Kummer theory
Meeting agenda: Ajmain will give a brief review of Chapter 1: Kummer Theory and move on to present the first two sections of Chapter 11: Hilbert 90, Section 1: Hilbert 90 in Galois cohomology and Section 2: More Kummer theory. If there is time, Ajmain will prove Proposition 7.18 of Section 3: First applications: cyclic groups of Chapter 7: Combinatorial Constructions, which will be relevant for Valera's presentation next week.
Speaker: Valera Sergeev
Title: The Hilbert symbol
Meeting agenda: Valera will complete the presentation of Chapter 11: Hilbert 90 by presenting Section 3: The Hilbert symbol. If there is time, we will do exercises.
There will be weekly meetings on Mondays at 12:00 PM - 1:45 PM.
The meetings will be at the Graduate Center, Math Thesis Room (4214.03).
Depending on interest, we may stream the talks through zoom. Email ayamin(at)gradcenter(dot)cuny(dot)edu if you are interested in participating in the seminar but cannot attend in-person.
Speaker: Ajmain Yamin
Title: Review of Galois Cohomology
Meeting agenda: Ajmain will give a review of the first three chapters of Part III: Galois Cohomology, namely, Chapter 9: Ext and Tor, Chapter 10: Group Cohomology and Chapter 11: Hilbert 90.
Speaker: Valera Sergeev
Title: Shapiro's isomorphism and A few explicit formulae
Meeting agenda: Valera will begin presenting Chapter 12: Finer Structure by presenting Section 1: Shapiro's isomorphism and Section 2: A few explicit formulae.
Speaker: Connor Stewart
Title: The corestriction
Meeting agenda: Connor presented most of Chapter 12, Section 3: The corestriction.
Speaker: Connor Stewart
Title: The conjugation action
Meeting agenda: Connor will present the rest of Section 3 and present Section 4: The conjugation action.
Speaker: Ajmain Yamin
Title: The five-term exact sequence
Meeting agenda: Ajmain will begin presenting Section 5: The five-term exact sequence.
Speaker: Ajith Nair
Title: Cup-products
Meeting agenda: Ajith will begin presenting Section 6: Cup-products.
Speaker: Ajith Nair
Title: Cup-products
Meeting agenda: Ajith will continue presenting Section 6: Cup-products.
Speaker: Ajith Nair and Valera Sergeev
Title: Cup-products, Milnor and Bloch-Kato
Meeting agenda: Ajith will finish presenting Section 6: Cup-products and Valera will present Section 7: Milnor and Bloch-Kato. If there is time remaining, we will do some exercises from Chapter 12: Finer Structure.
Speaker: N/A
Title: Exercises from Chapter 12: Finer Structure
Meeting agenda: This will probably be the last meeting of the semester. We will do exercises from Chapter 12: Finer Structure.
There will meetings every other Friday from 10:00 AM - 11:00 AM.
The meetings will be at the Graduate Center, Math Thesis Room (4214.03).
Email ayamin(at)gradcenter(dot)cuny(dot)edu if you wish to be put on the mailing list.
Speaker: Ajmain Yamin
Title: Statements of Local Class Field Theory
Meeting agenda: Ajmain started presenting Chapter 13: Local Class Field Theory of Part IV: Class Field Theory of Guillot's book.
Speaker: Connor Stewart
Title: Cohomological triviality and equivalence
Meeting agenda: Connor will present Section 2: Cohomological triviality and equivalence of Chapter 13. The goal is to prove Tate's theorem which will be used to deduce the reciprocity theorem of local class field theory.
Speaker: Connor Stewart and Ajmain Yamin
Title: Cohomological triviality and equivalence
Meeting agenda: Connor finished presenting Section 2: Cohomological triviality and equivalence of Chapter 13. Then Ajmain presented the proof of Proposition 8.4, showing that the norm subgroups corresponding to the degree n unramified extensions of a local number field are precisely the kernels of the valuation map mod n.
Speaker: Ajmain Yamin
Title: The Brauer group of a local number field
Meeting agenda: Ajmain will begin the meeting by presenting Chapter 8: The Brauer group of a local number field. Ajmain will present Section 8.2: The Hasse invariant of a skewfield and Section 8.3: Naturality.
Speaker: Ajmain Yamin
Title: The Brauer group of a local number field
Meeting agenda: Ajmain continued presenting Chapter 8: The Brauer group of a local number field.
Speaker: Valera Sergeev
Title: Norms subgroups
Meeting agenda: Valera will present Section 14.2: The reciprocity isomorphisms and Section 14.3: Norm subgroups.
There will meetings every Wednesday from 12:00 PM - 1:00 PM.
The meetings will be at the Graduate Center, Math Thesis Room (4214.03).
Email ayamin(at)gradcenter(dot)cuny(dot)edu if you wish to be put on the mailing list.
Speaker: Ajmain Yamin
Title: Review and the Existence theorem
Meeting agenda: Ajmain will review what has been covered of Chapter 13: Local Class Field Theory so far. Namely, the first four sections. Then, Ajmain presented Section 13.6: The Existence theorem.
Speaker: Ajith Nair
Title: Tate duality
Meeting agenda: Ajith will present Section 13.5: Tate duality.
Speaker: Ajmain Yamin
Title: Tate duality
Meeting agenda: Ajmain will finish presenting Section 13.5: Tate duality.
Speaker: Valera Sergeev
Title: The local Kronecker-Weber theorem
Meeting agenda: Valera will present Section 13.6: The local Kronecker-Weber theorem.
Speaker: Valera Sergeev
Title: The local Kronecker-Weber theorem
Meeting agenda: Valera will finish presenting Section 13.6 and some relevant lemmas from Part I of the book.
Speaker: Connor Stewart
Title: A concise reformulation
Meeting agenda: Connor will present Section 13.7: A concise reformulation. If there is time remaining, Connor will start presenting Chapter 14: Global Class Field Theory.
Speaker: Connor Stewart
Title: Number fields, their completions, the discriminant & the (global) Kronecker-Weber theorem
Meeting agenda: Connor will present Section 14.1: Number fields and their completions, Section 14.2: The discriminant, and Section 14.3: The (global) Kronecker-Weber Theorem.
Speaker: Joseph DiCapua
Title: Formal Group Laws and Explicit Local Class Field Theory
Meeting agenda: Joe will give an introduction to Lubin-Tate formal group laws and the application to explicit local class field theory.