70 citations · 480 across the 69 of their papers we have counts for
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Large scale geometry of commutator subgroups
Danny Calegari, Dongping Zhuang
Let G be a finitely presented group, and G' its commutator subgroup. Let C be the Cayley graph of G' with all commutators in G as generators. Then C is large scale simply connected…
Combable functions, quasimorphisms, and the central limit theorem
Danny Calegari, Koji Fujiwara
A function on a discrete group is weakly combable if its discrete derivative with respect to a combing can be calculated by a finite state automaton. A weakly combable function is…
Surface subgroups from homology
Danny Calegari
Let G be a word-hyperbolic group, obtained as a graph of free groups amalgamated along cyclic subgroups. If H_2(G;Q) is nonzero, then G contains a closed hyperbolic surface subgrou…
Stable commutator length is rational in free groups
Danny Calegari
For any group, there is a natural (pseudo-)norm on the vector space B1 of real (group) 1-boundaries, called the stable commutator length norm. This norm is closely related to, and…