# Beyond an intro to topological graph theory…

I'm looking to find out what active areas of research there are in topological graph theory, particularly those that interface strongly with other areas of math (say, group theory, algebraic topology, Gromov-Witten theory, etc).

Assuming a background given by, say, Topological Graph Theory by Gross and Tucker (a standard reference):

(1) How does topological graph theory fit into and interface with 21st century mathematics, and where is the field going?

(2) I'm particularly interested in applications to algebraic topology and algebraic geometry - can anyone summarize these or give a feel for what the most active areas are?

I wouldn't describe it as an "area" of math, exactly, but there are certainly mathematicians who study embeddings of graphs into surfaces and related objects. Let me recommend two sources to learn more about what people are doing. I am not familiar with the book you listed, so I don't know if it sufficient preparation for reading them; however, I am a big fan of jumping in to an unknown field and then learning background information "as you go".

The first is the long book

MR2036721 (2005b:14068) Lando, Sergei K.(RS-IUM-M); Zvonkin, Alexander K.(F-BORD-LB) Graphs on surfaces and their applications. With an appendix by Don B. Zagier. Encyclopaedia of Mathematical Sciences, 141. Low-Dimensional Topology, II. Springer-Verlag, Berlin, 2004. xvi+455 pp. ISBN: 3-540-00203-0

This might be the closest to what you are looking for in that it focuses on connections with algebraic geometry and number theory, especially Grothendieck's theory of dessins d'enfants and questions related to the moduli space of curves.

The second is a very different direction, namely the study of "spatial graphs"; ie embeddings of graphs into 3-space and other 3-manifolds. This is basically a generalization of knot theory. One possible way of getting into this subject is to start with the survey

MR2179645 (2006e:57009) Ramírez Alfonsín, J. L.(F-PARIS6-CM) Knots and links in spatial graphs: a survey. (English summary) Discrete Math. 302 (2005), no. 1-3, 225--242.

• Ah, that book looks great, thanks! Can you (or anyone else) comment here on some of the main applications to the moduli space of curves or 3-manifolds? – Dr Shello Sep 23 '10 at 0:30
• You might find the following question enlightening : mathoverflow.net/questions/190/… – Andy Putman Sep 23 '10 at 3:14
• If you want something longer than an MO answer but shorter than a whole book to tell you a bit about the algebraic applications of dessins d'enfant, see ams.org/notices/200307/what-is.pdf or en.wikipedia.org/wiki/Shabat_polynomial (using an alternative name for the WP article because MathOverflow doesn't like URLs with apostrophes in them) – David Eppstein 10 secs ago – David Eppstein Sep 23 '10 at 4:59