Math 154
Graph Theory

Spring 2023

Instructor: Gwen McKinley (gmckinley@ucsd.edu)
Course email address: 154-staff-G@ucsd.edu

Lectures: 1-1:50pm on MWF, in York Hall 2622
Discussion sections: Thursday afternoons

Office hours:

Time Room Person
Mondays   2-4pm AP&M 6402 Gwen McKinley and Nicholas Sieger
Tuesdays   9-11am AP&M 5801 Erlang Surya
Tuesdays   11am-12pm HSS 5041 Shubham Sinha
Fridays   10-11am HSS 4062 Emily Zhu
Fridays   2-3pm AP&M B412 Gwen McKinley

Finals week office hours:

Individual meetings: if you have a private issue you'd like to discuss, you can request a one-on-one appointment here.


Course information

For information on grading, textbook, acommodations, and more: see the Course Syllabus.

Due dates: here is a calendar of all homework due dates and quiz and exam dates.

Quizzes: There will be three Canvas quizzes, held on the dates below. Each quiz will be available during a 24-hour window (12am-11:59pm Pacific Time), and you will have 30 minutes to finish each quiz once you have begun.

Exams: There will be one in-person midterm exam and an in-person final exam, on the following dates:


Homework

Weekly homework assignments will be posted here. Homework is due by 11:59pm on Wednesdays, through Gradescope. The due dates are also listed on the calendar of assignments.
Note: there may be some slight changes to the assigments posted below (e.g., shifting a problem to a later homework), but I will do my best to finalize each assignment no later than one week before its due date.


Lecture schedule

Here is a tentative schedule of what will be covered in each lecture, together with the relevant section(s) of the book: Introduction to Graph Theory (Course Notes), by Professor Jacques Verstraete. This is a rough schedule, and there will be some give and take between lectures.

Week Date Topic Book Sections
1 4/3 Definition and basic properties of graphs (warm-up, slide 1, slide 2) 1,1. 1.4
4/5 Basic classes of graphs, Handshaking Lemma (warm-up, slide 1) 1.3, 1.5
4/7 Subgraphs, walks (warm-up, slide 1, slide 2) 1.6, 1.7, 2.1
2 4/10 Connected graphs, Eulerian graphs (warm up, slide 1) 2.2, 2.3
4/12 Finish Eulerian graphs, start Hamiltonian graphs
(Example of Hierholzer's Algorithm)
2.3, 2.5
4/14 Finish Hamiltonian graphs 2.5
3 4/17 Bridges and trees (slide 1, warm-up, slide 2) 3.1
4/19 Finish trees, depth-first search 3.1, 3.4
4/21 BFS, Characterizing bipartite graphs (warm-up, slide 1) 3.2, 3.3
4 4/24 Characterizing bipartite graphs (warm-up, slide 1) 3.3
4/26 Prim's and Kruskal's Algorithms (warm-up, slide 1, slide 2) 3.5
4/28 Independent sets and covers (warm-up, slide 1, slide 2, slide 3) 5.1
5 5/1 Finish independent sets and covers 5.1
5/3 Hall's Theorem (warm-up) 5.2
5/5 Finish Hall's Theorem 5.2
6 5/8 Edge coloring, Konig's Theorem (warm-up, slide 1, slide 2) 6, 6.1
5/10 Midterm
5/12 Finish Konig's Theorem (warm-up, slide 1) 6.1
7 5/15 Intro to vertex coloring (warm-up, slide 1, slide 2) 6
5/17 Degenrate graphs, start Brooks' Theorem (warm-up, notes) 6.4, 6.3
5/19 Finish Brooks' Theorem (notes) 6.3
8 5/22 Planar graphs, Euler's formula (warm-up, slide 1) 7.1
5/24 More on planar graphs, Kuratowski's Theorem, Wagner's Theorem 7.3
5/26 Coloring planar graphs (warm-up, slides) 7.3
9 5/29 No Class (Memorial Day)
5/31 Flows, capacities, and cuts (warm-up, slide 1, slide 2) 8.1-8.3
6/2 The Ford Fulkerson Algorithm 8.4
10 6/5 The Max-Flow Min-Cut Theorem (warm-up, slide 1, slide 2) 8.3
6/7 Fun problems :)
6/9 Review
Finals 6/15 Final Exam (Thursday of finals week, 3-6pm)