We discuss free subsemigroups in solvable and elementary amenable groups improving earlier results of Milnor-Wolf, Rosenblatt, Alperin and Osin about uniform exponential growth for these groups.

This paper argues that growth theory needs a more general notion of “regularity” than that of exponential growth. We suggest that paths along which the rate of decline of the growth rate is proportional to the growth rate itself deserve attention. This opens up for considering a richer set of parameter combinations than in standard growth models. Moreover, it avoids the usual oversimplistic dic...

There do not exist context–free languages of intermediate growth. The function γ whose value at each non–negative integer n is the number of words on length n in a fixed formal language L is called the growth function of L. Flajolet [3] asked if there are context–free languages of intermediate growth; that is, such that γ is not bounded above by a polynomial, but lim sup γ(n)/r = 0 for all r > ...

An n-dimensional polyhedral space is a length space M (with intrinsic metric) triangulated into n-simplexes with smooth Riemannian metrics. In the definitions below, we assume that the triangulation is fixed. The boundary of M is the union of the (n− 1)-simplexes of the triangulation that are adjacent to only one (n− 1)-simplex. As usual, a geodesic in M is a naturally parametrized locally shor...

We prove that if the group generated by an invertible and reversible Mealy automaton acts level-transitively on a regular rooted tree, then the semigroup generated by the dual automaton has exponential growth, hence giving a decision procedure of exponential growth for a restricted family of automaton (semi)groups. The purpose of this note is to link up two classes of groups and semigroups high...

Software reliability growth model is one of the basic techniques to assess software reliability quantitatively and it provides the essential information for software development activities. In this paper we compare the predictive capability of popular software reliability growth models (SRGM), such as exponential growth, delayed S-shaped growth and inflection S-shaped growth models. We first re...

In this paper‎, ‎we prove a multiplicity result for some biharmonic elliptic equation of Kirchhoff type and involving nonlinearities with critical exponential growth at infinity‎. ‎Using some variational arguments and exploiting the symmetries of the problem‎, ‎we establish a multiplicity result giving two nontrivial solutions‎.

Most models of tumorigenesis assume that the tumor grows by increased cell division. In these models, it is generally supposed that daughter cells behave as do their parents, and cell numbers have clear potential for exponential growth. We have constructed simple mathematical models of tumorigenesis through failure of programmed cell death (PCD) or differentiation. These models do not assume th...