Strongly regular edge-transitive graphs

In this paper, we examine the structure of vertex- and edge-transitive strongly regular graphs, using normal quotient reduction. We show that the irreducible graphs in this family have quasiprimitive automorphism groups, and prove (using the Classification of Finite Simple Groups) that no graph in this family has a holomorphic simple automorphism group. We also find some constraints on the parameters of the graphs in this family that reduce to complete graphs.Comment: 23 page

Vassiliev knot invariants and Chern-Simons perturbation theory to all orders

At any order, the perturbative expansion of the expectation values of Wilson lines in Chern-Simons theory gives certain integral expressions. We show that they all lead to knot invariants. Moreover these are finite type invariants whose order coincides with the order in the perturbative expansion. Together they combine to give a universal Vassiliev invariant.Comment: Revised version, includes a detailed proof of formula (5.26) for $\log Z$, and several minor changes. 31 pages, 19 figures, epsf.sty, Late