In this article we relate word and subgroup growth to certain functions that
arise in the quantification of residual finiteness. One consequence of this
endeavor is a pair of results that equate the nilpotency of a finitely
generated group with the asymptotic behavior of these functions. The second
half of this article investigates the asymptotic behavior of two of these
functions. Our main result in this arena resolves a question of Bogopolski from
the Kourovka notebook concerning lower bounds of one of these functions for
nonabelian free groups.
In this article we investigate the L^1-norm of certain functions on groups
called divisibility functions. Using these functions, their connection to
residual finiteness, and integration theory on profinite groups, we define the
residual average of a finitely generated group. One of the main results in this
article is the finiteness of residual averages on finitely generated linear
groups. Whether or not the residual average is finite depends on growth rates
of indices of finite index subgroups.