5 papers
Counting maps from a surface to a graph
Mladen Bestvina, Mark Feighn
Let F be a non-abelian finite rank free group, and let H_g be the fundamental group of a surface of genus g with one boundary component represented by D_g in H_g. So, H_g is the fr…
Proper actions of lattices on contractible manifolds
Mladen Bestvina, Mark Feighn
Every lattice H in a connected semi-simple Lie group G acts properly discontinuously by isometries on the contractible manifold G/K (K a maximal compact subgroup of G). We prove th…
Solvable subgroups of Out(F_n) are virtually abelian
Mladen Bestvina, Mark Feighn, Michael Handel
A companion result of the the Tits alternative for is proved: Every solvable subgroup of is finitely generated and virtually abelian.
The Tits Alternative for II: A Kolchin Type Theorem
Mladen Bestvina, Mark Feighn, Michael Handel
The proof of the Tits alternative for is completed. The main tool is a Kolchin type theorem, proved in this paper. It states that a finitely generated subgroup of $Out(F…
The Tits alternative for Out(F_n) I: Dynamics of exponentially-growing automorphisms
Mladen Bestvina, Mark Feighn, Michael Handel
The Tits alternative for Out(F_n) is reduced to the case where all elements in the subgroup under consideration grow polynomially.