An Upper Bound for the Lower Central Series Quotients of a Free Associative Algebra
Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Correspondence: Correspondence to be sent to: galyna{at}mit.edu
Feigin and Shoikhet conjectured in [4], Feigin and Shoikhet, Mathematical Research Letters, 14,2007,781–95 that successive quotients Bm(An) of the lower central series filtration of a free associative algebra An have polynomial growth. In this paper we give a proof of this conjecture, using the structure of a representation of Wn, the Lie algebra of polynomial vector fields on
, on Bm(An) which was defined in [4]. Moreover, we show that the number of squares in a Young diagram D corresponding to an irreducible Wn-module in the Jordan–Hölder series of Bm(An) is bounded above by the integer
, which allows us to confirm the structure of B3(A3) conjectured in [4].