18.102 Intro to Functional Analysis

Welcome to 18.102: Introduction to functional analysis

  • Syllabus: vector spaces, topological spaces, metric spaces, completeness, Baire category theorem, normed and Banach spaces, Hahn-Banach theorem, open mapping theorem, closed graph theorem, (some) abstract measure theory, Lebesgue measure, Lebesgue integration, L^p spaces, dual spaces and weak topologies, Banach-Alaoglu theorem, Hilbert spaces, compact operators, spectral theorem. 
  • Prerequisites: Linear algebra (18.06, 18.700, or 18.701) and real analysis (18.100A, 18.100B, 18.100P, 18.100Q) or permission from the lecturer.
  • Homework: There will be 7 problem sets in total. Only the best 6 problem sets count towards your final grade. No late homework will be accepted except for cases approved by S3 (https://studentlife.mit.edu/s3).
  • Grading: The final grade is the weighted average of the problem sets (30%, i.e. 5% for each problem set), the two midterms (30%, i.e. 15% each), and the final (40%). 
  • Office hours:
      • Christoph Kehle: Tuesday, 1.30 pm-2.30 pm, 2-277, kehle@mit.edu (NO OFFICE HOUR ON MAY 13) 
      • Ryan Chen: Thursday 10 am - 11 am, 2-255, rcchen@mit.edu
        • Ryan will have office hours from 2 PM to 3 PM on Zoom on Saturday May 10, 2025 (moved due to travel).
      • Divya Shyamal: Mondays, 5:30 - 6:30 pm (ending May 9 - by appointment after), Zoom, dshyamal@mit.edu
  • Exams: There will be two midterms on 3 March and 9 April and one final on 21 May.
  • Lecture notes
  • Problem sets:
  • Solutions:
  • Midterms:

 

Lecture number Date Notes Contents Pset number Pset due (at 11.59pm)
1 2/3/2025 Zorn's lemma, topological spaces
2 2/5/2025 Continuity, compactness, Tychnoff's theorem
3 2/10/2025 Metric spaces, completeness, completion
4 2/12/2025 l^p, C(K) spaces and their completeness  1 2/14/2025 (Friday)
5 2/18/2025 moved from 2/17/2025 Baire category theorem and applications, normed spaces, Banach spaces
6 2/19/2025 Riesz' lemma, linear operators 
7 2/24/2025 Hahn--Banach theorem, Banach Steinhaus theorem 2 2/24/2025
8 2/26/2025 Open mapping theorem, closed graph theorem, inverse mapping theorem 
9 3/3/2025 midterm, in class
10 3/5/2025

Measure spaces, outer measures

11 3/10/2025 Carathéodory extension theorem and Lebesgue measure 3 3/13/2025
12 3/12/2025 Approximation theorems for Lebesgue measures, Hausdorff measure
13 3/17/2025 Measurable functions and integration,
14 3/19/2025

Convergence theorems, L^p spaces

Spring break 3/24/2025
Spring break 3/26/2025
15 3/31/2025

Completeness of L^p spaces, Dual spaces, weak topologies, Locally convex spaces

4 3/31/2025
16 4/2/2025

Banach-Alaoglu theorem

17 4/7/2025 Riesz representation for L^p spaces
18 4/9/2025 midterm, in class
19 4/14/2025

Hilbert spaces, Orthogonality

5 4/16/2025
20 4/16/2025

Projection theorem, Riesz representation theorem for Hilbert space,

Patriots' day 4/21/2025 no lecture
Drop date 4/22/2025
21 4/23/2025

Bessel's inequality, Parseval's identity

22 4/28/2025

Hilbert-Adjoint Operator, Spectral theory on Banach spaces

6 4/28/2025
23 4/30/2025 Compact operators 
24 5/5/2025

Arzela Ascoli, Schauder's theorem

25 5/7/2025 Spectral theorem for compact self-adjoint operators 
26 5/12/2025 Fredholm alternative, exam prep 7

5/12/2025

(Friday)

Final exam  21 May

in person: 120 min 

 

 

Course Summary:

Date Details Due