Papers

Click after the title to see the paper (requires either a dvi or ps viewer).
NOTE: Figures appear only in the ps and pdf files.

• The rational cohomology of the mapping class group vanishes
  in its virtual cohomological dimension pdf
  (with T. Church and A. Putman), Inter. Math. Res. Notices , to appear.
  
  
• On the geometric nature of characteristic classes of surface bundles pdf
  (with T. Church and M. Thibeault), preprint, 24 pages, revised May 2011.
  
  
• Representation theory and homological stability. pdf
  (with T. Church), preprint, 89 pages, revised October 2011.
  
  
• Remembering John Stallings pdf
  (edited with D. Calegari), Notices of the AMS, Vol. 56, No. 11, Dec. 2009, p.1410-1417.
  
  
• The extremal symmetry of arithmetic simplicial complexes. pdf
  (with A. Mohammadi), preprint, 17 pages, revised August 2011.
  
  
• Parameterized Abel-Jacobi maps and abelian cycles in the Torelli group pdf
  (with T. Church), Jour. of Topology, to appear.
  
  
• Infinite generation of the kernels of the Magnus and Burau representations. pdf
  (with T. Church), Alg. and Geom. Top. (AGT), 10 (2010), no. 2, 837--851.
  Click here for the accompanying Mathematica Notebook.
  
  
• Small dilatation pseudo-Anosovs and 3-manifolds. pdf
  (with C. Leininger and D. Margalit), Advances in Math. , Vol. 228 (2011), 1466--1502.
  
  
• Teichmuller geometry of moduli space, II: M(S) seen from far away. pdf
  (with H. Masur), In the tradition of Ahlfors-Bers. V, 71--79,
  Contemp. Math., 510, Amer. Math. Soc., 2010.
  
  
• Rigidity, locally symmetric varieties and the Grothendieck-Katz Conjecture. ps or pdf
  (with M. Kisin), Inter. Math. Res. Notices , Vol. 2009, No.22, pp. 4159-4167.
  
  
• Group actions and Helly's theorem ps or pdf
  Advances in Math, Vol. 222, Issue 5, 1574-1588 (2009).
  
  
• The intrinsic asymmetry and inhomogeneity of Teichmuller space. pdf
  (with S. Weinberger), Duke Math. Journal, Vol. 155, No. 1, 91--103.
  
  
• Problems on automorphism groups of nonpositively curved
  polyhedral complexes and their lattices. ps or pdf
  (with C. Hruska and A. Thomas), 38 pages, to appear in
  Geometry, Topology and Rigidity (B. Farb and D. Fisher, eds.).
  
  
• Teichmuller geometry of moduli space, I: Distance minimizing rays and
  the Deligne-Mumford compactification. ps or pdf
  (with H. Masur), Jour. Diff. Geom., Vol. 85 (2010), 187--227.
  
  
• Irreducible Sp-representations and subgroup distortion in the
  mapping class group. pdf
  (with N. Broaddus and A. Putman), to appear in Comment. Math. Helv. , Vol. 86, No. 3 (2011), 537--556.
  
  
• The Casson invariant and the word metric on the Torelli group. ps or pdf
  (with N. Broaddus and A. Putman), C.R. Acad. Sci Paris, Vol. 345 (2007),
  no. 8, 449--452.
  
  
• Commensurations of Out(F_n). ps or pdf
  (with Michael Handel), Publ. Math. IHES., No. 105 (2007), 1--48.
  
  
• (Book) Problems on Mapping Class Groups and Related Topics. pdf
  This is a (June 2006) version of a book that appeared as
  Proc. Symp. Pure and Applied Math., Volume 74, 2006.
  It is the final online version. 402 pages.
  
  
• Some problems on mapping class groups and moduli space. dvi or ps or pdf
  in ``Problems on Mapping Class Groups and Related Topics",
  ed. by B. Farb, Proc. Symp. Pure and Applied Math., Vol. 74, pp. 11-55, June 2006.
  
  
• The lower central series and pseudo-Anosov dilatations. ps or pdf
  (with C. Leininger and D. Margalit), American Jour. Math, 130 (2008), no. 3, 799--827.
  
  
• The Birman-Craggs-Johnson homomorphism and abelian cycles in the
  Torelli group. dvi or ps or pdf
  (with T. Brendle), Math. Annalen, 338 (2007), no. 1, 33--53.
  
  
• Isometries, rigidity and universal covers. dvi or ps or pdf
  (with S. Weinberger), Annals of Math, Vol. 186, No.3, p.915-940 (2008)
  
  
• Commensurability invariants for nonuniform tree lattices. dvi or ps or pdf
  (with C. Hruska), Israel Jour. Math. 152 (2006), 125--142.
  
  
• Hidden symmetries and arithmetic manifolds. dvi or ps or pdf
  (with S. Weinberger), in Geometry, spectral theory, groups, and dynamics ,
  Contemp. Math., Vol. 387, Amer. Math. Soc., pp. 111--119.
  
  
• The Torelli Geometry and its applications. dvi or ps or pdf
  (with N. Ivanov), Math. Research Letters., Vol. 12, pp. 293-301 (2005).
  
  
• Every mapping class group is generated by 6 involutions. dvi or ps or pdf
  (with T. Brendle), Journal of Algebra. , Vol. 278 (2004), 187-198.
  
  
• Some recent applications of the barycenter method in geometry. dvi or ps or pdf
  (with C. Connell), in Topology and Geometry of Manifolds ,
  Proc. Symp. in Pure Math., G. Matic and C. McCrory, Eds., 2003, 19--51.
  
  
• The Degree Theorem in higher rank. dvi or ps or pdf
  (with C. Connell), J. Diff. Geom., Vol. 65 (2003), 19--59.
  
  
• Real-analytic, volume-preserving actions of lattices on 4-manifolds. dvi or ps or pdf
  (with P. Shalen), C.R. Acad. Sci Paris, Ser. I, Vol. 334 (2002), 1011-1014.
  
  
• Curvature and rank of Teichmuller space. dvi or ps or pdf
  (with J. Brock), American Jour. Math. , Vol. 128, No. 1 (2006), pp. 1-22.
  
  
• Groups of homeomorphisms of one-manifolds, III: Nilpotent subgroups. dvi or ps or pdf
  (with J. Franks), Ergodic Theory Dynam. Systems 23 (2003), no. 5, 1467--1484
  
  
• Convex cocompact subgroups of mapping class groups. dvi or ps or pdf
  (with L. Mosher), Geometry and Topology, Vol. 6 (2002), 91-152.
  
  
• Groups of homeomorphisms of one-manifolds, I: Actions of nonlinear groups . dvi or ps or pdf
  (with J. Franks), June 2001 preprint, 28 pages.
  
  
• Groups of homeomorphisms of one-manifolds, II: Extensions of Holder's Theorem. dvi or ps or pdf
  (with J. Franks), Trans. Amer. Math. Soc. , Vol. 355 (2003), no. 11, 4385--4396.
  
  
• A strong Schottky Lemma for nonpositively curved singular spaces. dvi or ps or pdf
  (with R. Alperin and G. Noskov), Geometriae Dedicata , Vol. 92 (2002), 235--243.
  
  
• The geometry of surface-by-free groups. dvi or ps or pdf
  (with L. Mosher), Geom. Funct. Anal (GAFA), Vol.12 (2002), no. 5, 915--963.
  
  
• Minimal entropy rigidity for lattices in products of rank one symmetric spaces. dvi or ps or pdf
  (with C. Connell). Comm. in Anal. and Geom. 11 (2003), no. 5, 1001--1026.
  
  
• Rank one phenomena for mapping class groups. dvi or ps or pdf
  (with A. Lubotzky and Y. Minksy). Duke Math Journal, Vol. 106, No.3 (2001), 581-597.
  
  
• Problems on the geometry of finitely generated solvable groups. dvi or ps or pdf
  (with L. Mosher), in ``Crystallographic Groups and their Generalizations (Kortrijk, 1999)'',
  (ed. P. Igodt, et. al.), Cont. Math. 262, Amer. Math. Soc. (2000).
  
  
• On the asymptotic geometry of abelian-by-cyclic groups. dvi or ps or pdf
  (with L. Mosher). Acta Math. , Vol. 184, No.2 (2000), 145-202.
  
  
• Groups of real-analytic diffeomorphisms of the circle. dvi or ps
  (with P. Shalen). Ergodic Theory and Dynam. Syst. , Vol. 22 (2002), 835-844.
  
  
• Lattice actions, 3-manifolds, and homology. dvi or ps
  (with P. Shalen). Topology , Vol. 39 (2000), no. 3, 573-587.
  
  
• Real-analytic actions of lattices. dvi or ps
  (with P. Shalen). Inventiones Math. , Vol. 135 (1998), 273-296.
  
  
• A remark about actions of lattices on free groups. dvi or ps
  (with M. Bridson). Topology Appl. , Vol. 110, No. 1 (2001), 21-24.
  
  
• Harmonic splittings of surfaces. dvi or ps
  (with M. Wolf). Topology, Vol. 40, No.6 (2001), 1395-1414.
  
  
• Superrigidity and mapping class groups. dvi or ps
  (with H. Masur). Topology , Vol. 37, No.6 (1998), 1169-1176.
  
  
• Quasi-isometric rigidity for the solvable Baumslag-Solitar groups, II. dvi or ps
  (with L. Mosher) Inventiones Math. , Vol. 137 (1999), No. 3, 273-296.
  
  
• The quasi-isometry classification of lattices in semisimple Lie groups. dvi or ps
  Math. Res. Letters, Vol. 4, No.5, Sept. 1997, 705-718.
  
  
• A rigidity theorem for the solvable Baumslag-Solitar groups. dvi or ps
  (with L. Mosher). Inventiones Math. , Vol. 131, No.2 (1998), 419-451.
  
  
• Quasi-flats and rigidity in higher rank symmetric spaces. dvi or ps
  (with A. Eskin). Journal AMS. , Vol. 10, No.3, July 1997, 653-692.
  
  
• Quasi-flats in H²xH². dvi or ps
  (with A. Eskin). Proceedings of the International Colloquium on Lie groups and
  Ergodic Theory, Tata Institute 1996.
  
  
• The large-scale geometry of Hilbert modular groups. dvi or ps
  (with R. Schwartz). J. Diff. Geom. 44, No.3 (1996), 435-478.
  
  
• Relatively hyperbolic groups. dvi or ps
  Geom. Funct. Anal. (GAFA), Vol.8 (1998), 1-31.
  
  
• Filling-invariants at infinity for manifolds of nonpositive curvature. dvi or ps
  (with N. Brady). Trans. Amer. Math. Soc., Vol.350, No.8 (1998), 3393-3405.
  
  
• Relatively hyperbolic and automatic groups with applications to negatively curved manifolds.
  Thesis, Princeton University, May 1994.
  
  
• Combing lattices in semisimple Lie groups. dvi or ps
  Groups - Korea '94, Proceedings of the international conference, ed. by A.C. Kim and
  D.L. Johnson, deGruyter 1994, 57-67.
  
  
• The Extrinsic geometry of subgroups and the generalized word problem. dvi or ps
  Proc. London Math. Soc. (3) 68 (1994), 577-593.
  
  
• (Book)Noncommutative Algebra.
  (book with R.K. Dennis), Graduate Texts in Mathematics 144, 270 pages, Springer, New York, 1993.
  
  
• Automatic groups: A guided tour. dvi or ps
  L'Enseignement Math., Vol. 38 (1992), 291-313.