Type: Article
Publication Date: 2014-05-20
Citations: 43
DOI: https://doi.org/10.1515/crelle-2014-0030
Abstract We prove that the braided Thompson’s groups <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"> <m:msub> <m:mi>V</m:mi> <m:mi>br</m:mi> </m:msub> </m:math> {V_{\mathrm{br}}} and <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"> <m:msub> <m:mi>F</m:mi> <m:mi>br</m:mi> </m:msub> </m:math> {F_{\mathrm{br}}} are of type <m:math xmlns:m="http://www.w3.org/1998/Math/MathML"> <m:msub> <m:mi mathvariant="normal">F</m:mi> <m:mi mathvariant="normal">∞</m:mi> </m:msub> </m:math> {\rm F}_{\infty} , confirming a conjecture by John Meier. The proof involves showing that matching complexes of arcs on surfaces are highly connected. In an appendix, Zaremsky uses these connectivity results to exhibit families of subgroups of the pure braid group that are highly generating, in the sense of Abels and Holz.