Homotopy Gerstenhaber algebras and topological field theory
  We prove that the BRST complex of a topological conformal field theory is a homotopy Gerstenhaber algebra, as conjectured by Lian and Zuckerman in 1992. We also suggest a refinement of the original conjecture for topological vertex operator algebras. We illustrate the usefulness of our main tools, operads and "string vertices" by obtaining new results on Vassiliev invariants of knots and double loop spaces. 
Takashi Kimura (Boston University), Alexander A. Voronov (University   of Pennsylvania), and Gregg J. Zuckerman (Yale Univer...