Letters in Mathematical Physics

, Volume 26, Issue 1, pp 43–51

Link invariants of finite type and perturbation theory

  • John C. Baez

DOI: 10.1007/BF00420517

Cite this article as:
Baez, J.C. Lett Math Phys (1992) 26: 43. doi:10.1007/BF00420517


The Vassiliev-Gusarov link invariants of finite type are known to be closely related to perturbation theory for Chern-Simons theory. In order to clarify the perturbative nature of such link invariants, we introduce an algebra Vx containing elements gi satisfying the usual braid group relations and elements ai satisfying giginfisup-1ai, where ε is a formal variable that may be regarded as measuring the failure of ginfisup2to equal 1. Topologically, the elements ai signify intersections. We show that a large class of link invariants of finite type are in one-to-one correspondence with homogeneous Markov traces on Vx. We sketch a possible application of link invariants of finite type to a manifestly diffeomorphisminvariant perturbation theory for quantum gravity in the loop representation.

Mathematics Subject Classifications (1991)

81T13 57M25 20F36 

Copyright information

© Kluwer Academic Publishers 1992

Authors and Affiliations

  • John C. Baez
    • 1
  1. 1.Department of MathematicsUniversity of CaliforniaRiversideUSA

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