Growth of subalgebras and subideals in free Lie algebras
arXiv:1307.1438
Abstract
We investigate subalgebras in free Lie algebras, the main tool being relative growth and cogrowth functions. Our study reveals drastic differences in the behavior of proper finitely generated subalgebras and nonzero subideals. For instance, the \textit{growth} of a proper finitely generated subalgebra of a free Lie algebra , with respect to any fixed free basis , is exponentially small compared to the growth of the whole of . Quite opposite, the \textit{cogrowth} of any nonzero subideal is exponentially small compared to the growth of .
arXiv comment31 pages