F. Thomas Farrell

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In this paper, we introduce the notion of an EZ-structure on a group, an equivariant version of the Z-structures introduced by Bestvina [4]. Examples of groups having an EZ-structure include (1) torsion free δ-hyperbolic groups, and (2) torsion free CAT(0)-groups. Our first theorem shows that any group having an EZ-structure has an action by homeomor-phisms(More)
The coupling of ecology and evolution during range expansions enables mutations to establish at expanding range margins and reach high frequencies. This phenomenon, called allele surfing, is thought to have caused revolutions in the gene pool of many species, most evidently in microbial communities. It has remained unclear, however, under which conditions(More)
Nine coral survey methods were compared at ten sites in various reef habitats with different levels of coral cover in Kāne'ohe Bay, O'ahu, Hawai'i. Mean estimated coverage at the different sites ranged from less than 10% cover to greater than 90% cover. The methods evaluated include line transects, various visual and photographic belt transects, video(More)
We are interested in examples of compact, complete, locally CAT(-1) spaces X, and closed totally geodesic codimension two subspaces Y , with the property that ∂ ∞ ˜ X = S n+2 ∞ , and ∂ ∞ ˜ Y = S n ∞. We show that if the inclusion S n ∞ → S n+2 ∞ induced by the inclusion Y ⊂ X is knotted, then it is a totally wild knot (i.e. nowhere tame). We give examples(More)