44 citations · 112 across the 13 of their papers we have counts for
6 papers · 1 filter
Depth of free-by-cyclic groups
Spencer Dowdall, Yassine Guerch, Radhika Gupta +2
For a free group automorphism, we prove that its poset of attracting lamination orbits is a canonical invariant of the associated mapping torus. That is, if a free-by-cyclic group…
Orientable maps and polynomial invariants of free-by-cyclic groups
Spencer Dowdall, Radhika Gupta, Samuel J. Taylor
We relate the McMullen polynomial of a free-by-cyclic group to its Alexander polynomial. To do so, we introduce the notion of an orientable fully irreducible outer automorphism …
Isomorphisms between big mapping class groups
Juliette Bavard, Spencer Dowdall, Kasra Rafi
We show that any isomorphism between mapping class groups of orientable infinite-type surfaces is induced by a homeomorphism between the surfaces. Our argument additionally applies…
Endomorphisms, train track maps, and fully irreducible monodromies
Spencer Dowdall, Ilya Kapovich, Christopher J. Leininger
Any endomorphism of a finitely generated free group naturally descends to an injective endomorphism of its stable quotient. In this paper, we prove a geometric incarnation of this…
Cannon-Thurston maps for hyperbolic free group extensions
Spencer Dowdall, Ilya Kapovich, Samuel J. Taylor
This paper gives a detailed analysis of the Cannon--Thurston maps associated to a general class of hyperbolic free group extensions. Let denote a free groups of finite rank $…
Unbounded asymmetry of stretch factors
Spencer Dowdall, Ilya Kapovich, Christopher J Leininger
A result of Handel-Mosher guarantees that the ratio of logarithms of stretch factors of any fully irreducible automorphism of the free group and its inverse is bounded by a c…