Transparencies

for my lectures at the 2000 CIRM-DONET Workshop on Graph Theory are now available at http://www.math.gatech.edu/~thomas/SLIDE. For reference purposes, here is my original tentative plan. Topics on planarity and Hamiltonian graphs were not covered.

Graph planarity and related topics

I have given a similar lecture at the recent Graph Drawing conference. You can look up my transparencies for that talk.

Tree-decompositions of graphs

See the lecture notes written for the Catlin Memorial Workshop.

Planarity in linear time

Testing planarity is a fundamental algorithmic problem. There are linear-time algorithms, but they are fairly complicated. My favorite one is an algorithm by Shih and Hsu. I have written an exposition of their algorithm.

Linkless embeddings of graphs in 3-space

See N. Robertson, P. D. Seymour and R. Thomas, Linkless embeddings of graphs in 3-space, Bull. Amer. Math. Soc. 28 (1993), 84-89.

The Four-Color Theorem

Here is a brief web survey, and here is a survey that appeared in the Notices of the AMS.

Excluded minor theorems

Here are transparencies for a similar lecture I have given at the 17th British Combinatorial conference, and here is the survey paper.

Hadwiger's conjecture for K6-free graphs

See N. Robertson, P. D. Seymour and R. Thomas, Hadwiger's conjecture for K6-free graphs, Combinatorica 13 (1993), 279-361.

Tutte's edge 3-coloring conjecture

With N. Robertson, D. P. Sanders and P. D. Seymour we managed to prove Tutte's edge 3-coloring conjecture that every 2-connected cubic graph with no Petersen minor is edge 3-colorable. By a result of Tait the conjecture implies the Four-Color Theorem. The proof is long and will occupy five papers. One of the five papers appeared in N. Robertson, P. D. Seymour and R. Thomas, J. Combin. Theory Ser. B. 70 (1997), 166-183.

Infinite graphs

With Robertson and Seymour we proved several structure theorems for excluding infinite minors. See our survey paper in N. Robertson, P. D. Seymour and R. Thomas, Excluding infinite minors, In: Directions in Infinite Graph Theory and Combinatorics, R. Diestel ed., North-Holland, 1992. There is also a newer result.

Polya's permanent problem

This includes material for at least two lectures. Here is the relevant paper, here is a relevant website, and here is an abstract for a talk I have given.

Hamiltonian graphs on surfaces

Tutte proved that every 4-connected planar graph is hamiltonian. This talk will be about various extensions of this result. See R. Thomas and X. Yu, 4-connected projective-planar graphs are Hamiltonian, J. Combin. Theory Ser. B 62 (1994), 114-132 and N. Dean, R. Thomas and X. Yu, Spanning paths in infinite planar graphs, J. Graph Thery 23 (1996), 163-174.

Digraph minors

Here are transparencies for a talk on directed tree-width, and here are transparencies for a talk I have given at the most recent SODA conference.

Coloring graphs on surfaces

The relevant manuscripts are Three-coloring Klein bottle graphs of girth five (with Barrett Walls), A new proof of the independence ratio of triangle-free cubic graphs (with Christopher Carl Heckman), Independent sets in triangle-free cubic planar graphs (with Christopher Carl Heckman).