A study on prefixes of c2 invariants. Algebraic Combinatorics, Resurgence, Moulds and Applications (CARMA), IRMA Lectures in Mathematics and Theoretical Physics 32 (2020). Also arXiv:1805.11735.
Forbidden minors for graphs with no first obstruction to parametric Feynman integration (with Samson Black, Iain Crump and Matt DeVos). Discrete Mathematics 338 (2015), 9-35. Also arXiv:1310.5788.
Towards a Combinatorial Understanding of Lattice Path Asymptotics (with Samuel Johnson and Marni Mishna). Advances in Applied Mathematics 92 (2018) 144-163. Also arXiv:1305.7418
Some combinatorial interpretations in perturbative quantum field theory. in "Feynman Amplitudes, Periods and Motives", Proceedings of the 2012 ICMAT workshop "Periods and Motives", Contemporary Mathematics, 648 (2015), 261-289. Also arXiv:1302.0080.
Recursion and growth estimates in
renormalizable quantum field theory (with Dirk Kreimer). Commun. Math. Phys.279, no.2, (2008), 401-427. (Also arXiv:hep-th/0612179.)
I haven't been putting most of my talks here lately. When I can I like to do board talks, and more and more places put up videos themselves, which are better than just the slides anyway, but here is a selection of slides from some talks I've given.
Counting trees with applications to counting Feynman diagrams March 14,
2006; CIRM conference on Renormalization and Galois theories. Available in postscript or pdf format.
Recursion and growth estimates in quantum field theory April 9,
2007; Johns Hopkins University. Available in postscript or pdf format.
Dyson-Schwinger equations and Renormalization Hopf algebras
April 10,
2007; Johns Hopkins University. Available in postscript or pdf format.
Feynman graphs to motives, June 28, 2007; Mathematische Arbeitstagung 2007. MPIM2007-75o.
Two different versions of a picture talk. Visualizing solutions to
Dyson-Schwinger equations, October 4, 2007, Boston University; available
in postscript or pdf format; and Rearranging
Dyson-Schwinger equations, October 7, 2007, Special Session on
Noncommutative Geometry and Arithmetic Geometry, AMS Fall Eastern Section
Meeting; available in postscript
or pdf format.
Two different versions of my job talk, A combinatorial perspective on Dyson-Schwinger equations. Simon Fraser University version, January 11, 2008; available in postscript or pdf format. McGill University version, February 14, 2008; available in postscript or pdf format.
Some scribbly talks from les Houches: Dyson-Schwinger equations I, II, III, and the animations from talk 3. June 17, 18, and 21, 2010. I also gave a fourth talk on the blackboard which was about spanning forest polynomials.
CMS Winter meeting 2010 talk. I had more material than time, so the later part of it isn't filled in.
Joint Mathematics Meeting 2011 talk in Victor Moll's session. The audience voted to see the knots and matroids instead of the picture proof of double triangle, so the latter is blank.
CMS Summer meeting 2012 talk about the chord diagram expansion.
This was supposed to be a bit of an overview for a physics audience along with a presentation of the QED Landau pole result, but it wasn't well timed nor well tailored to the audience. Perhaps it is more useful as slides.
My CanaDAM 2015 talk about the renormalization group equation.
Coast Combinatorics talk about leading log expansions.
CMS winter meeting talk about skew Schur function identities by Hopf algebras.
Two differentversions of a 2018 c2 talk for geometers and related mathematicians.
Les Houches workshop on structures in local quantum field theory talk about the c2 invariant.
An algebraic combinatorics talk on hourglass chains and my usual picture, very similar to an SFU discrete math talk the previous day.
An algebraic combinatorics talk on the Wilson Loop Diagram stuff with Susama Agarwala and Zee Fryer.
A Kolleg Mathematik Physik Berlin day talk on cut structures in Feynman diagrams.
