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Graph Theory

Discrete and Data

Networks from the ground up: degrees and isomorphism, connectivity, trees and spanning trees, shortest paths and minimum spanning trees, Euler and Hamilton tours, matchings, planarity, coloring, network flows, and Ramsey theory.

11 topics · 65 lessons about 28 hoursBefore this: Counting & Probability, Proof Writing & Problem Solving

What you'll be able to do

  • Model problems as graphs and prove facts with degree counting
  • Run and justify BFS, Dijkstra, Kruskal and Prim
  • Decide Eulerian, Hamiltonian, bipartite and planar questions
  • Use Hall, max-flow min-cut, coloring bounds and Ramsey arguments

Start the course

Go through each topic step by step — prose, worked examples, quick checks, and a timed practice round after every section.

Start

Every test ends with a score by topic and a list of what to revisit. Test out of a topic with 80% or better to mark it mastered.

Topics

1.

Graphs and Degrees

6 lessons

Vertices and edges, degree, the handshake lemma, and the graphs every course uses

2.

Isomorphism and Subgraphs

6 lessons

When two graphs are the same, and the invariants that prove they are not

3.

Walks, Paths and Connectivity

6 lessons

Walks and paths, components, counting walks with matrices, and weak points of a network

4.

Trees

6 lessons

The many equivalent definitions of a tree, spanning trees, and counting labeled trees

5.

Graph Algorithms

5 lessons

Searching a graph, shortest paths, and minimum spanning trees

6.

Eulerian and Hamiltonian Graphs

6 lessons

Traversing every edge, visiting every vertex, and the theorems that decide when you can

7.

Bipartite Graphs and Matchings

6 lessons

Two-sided graphs, matchings, Hall's marriage theorem, and stable matchings

8.

Planar Graphs

6 lessons

Drawing without crossings, Euler's formula, and the two forbidden graphs

9.

Graph Coloring

6 lessons

Chromatic number, greedy coloring, the chromatic polynomial, and edge coloring

10.

Directed Graphs and Network Flows

6 lessons

Digraphs and tournaments, strong connectivity, and the max-flow min-cut theorem

11.

Extremal Graph Theory and Ramsey Theory

6 lessons

How many edges force a triangle, and why complete disorder is impossible