Vogtmann has been the vice-president of the American Mathematical Society (2003–2006).[4][7] She has been elected to serve as a member of the board of trustees of the American Mathematical Society for the period February 2008 – January 2018.[8][9]
She is also a member of the ArXiv advisory board.[13]
Since 1986 Vogtmann has been a co-organizer of the annual conference called the Cornell Topology Festival[14] that usually takes places at Cornell University each May.
She gave the 2007 annual AWMNoether Lecture titled "Automorphisms of Free Groups, Outer Space and Beyond" at the annual meeting of American Mathematical Society in New Orleans in January 2007.[3][17] Vogtmann was selected to deliver the Noether Lecture for "her fundamental contributions to
geometric group theory; in particular, to the study of the automorphism group of a free group".[18]
On June 21–25, 2010 a 'VOGTMANNFEST' Geometric Group Theory conference in honor of Vogtmann's birthday was held in Luminy, France.[19]
In 2018 she won the Pólya Prize of the London Mathematical Society "for her profound and pioneering work in geometric group theory, particularly the study of automorphism groups of free groups".[30]
Vogtmann's most important contribution came in a 1986 paper with Marc Culler called "Moduli of graphs and automorphisms of free groups".[2] The paper introduced an object that came to be known as Culler–Vogtmann Outer space. The Outer space Xn, associated to a free groupFn, is a free group analog[35] of the Teichmüller space of a Riemann surface. Instead of marked conformal structures (or, in an equivalent model, hyperbolic structures) on a surface, points of the Outer space are represented by volume-one marked metric graphs. A marked metric graph consists of a homotopy equivalence between a wedge of n circles and a finite connected graph Γ without degree-one and degree-two vertices, where Γ is equipped with a volume-one metric structure, that is, assignment of positive real lengths to edges of Γ so that the sum of the lengths of all edges is equal to one. Points of Xn can also be thought of as free and discrete minimal isometric actions Fn on real trees where the quotient graph has volume one.
By construction the Outer space Xn is a finite-dimensional simplicial complex equipped with a natural action of Out(Fn) which is properly discontinuous and has finite simplex stabilizers. The main result of Culler–Vogtmann 1986 paper,[2] obtained via Morse-theoretic methods, was that the Outer space Xn is contractible. Thus the quotient spaceXn /Out(Fn) is "almost" a classifying space for Out(Fn) and it can be thought of as a classifying space over Q. Moreover, Out(Fn) is known to be virtually torsion-free, so for any torsion-free subgroupH of Out(Fn) the action of H on Xn is discrete and free, so that Xn/H is a classifying space for H. For these reasons the Outer space is a particularly useful object in obtaining homological and cohomological information about Out(Fn). In particular, Culler and Vogtmann proved[2] that Out(Fn) has virtual cohomological dimension 2n − 3.
In their 1986 paper Culler and Vogtmann do not assign Xn a specific name. According to Vogtmann,[36] the term Outer space for the complex Xn was later coined by Peter Shalen. In subsequent years the Outer space became a central object in the study of Out(Fn). In particular, the Outer space has a natural compactification, similar to Thurston's compactification of the Teichmüller space, and studying the action of Out(Fn) on this compactification yields interesting information about dynamical properties of automorphisms of free groups.[37][38][39][40]
Much of Vogtmann's subsequent work concerned the study of the Outer space Xn, particularly its homotopy, homological and cohomological properties, and related questions for Out(Fn). For example, Hatcher and Vogtmann[41][42] obtained a number of homological stability results for Out(Fn) and Aut(Fn).
In her papers with Conant,[43][44][45] Vogtmann explored the connection found by Maxim Kontsevich between the cohomology of certain infinite-dimensional Lie algebras and the homology of Out(Fn).
A 2001 paper of Vogtmann, joint with Louis Billera and Susan P. Holmes, used the ideas of geometric group theory and CAT(0) geometry to study the space of phylogenetic trees, that is trees showing possible evolutionary relationships between different species.[46] Identifying precise evolutionary trees is an important basic problem in mathematical biology and one also needs to have good quantitative tools for estimating how accurate a particular evolutionary tree is. The paper of Billera, Vogtmann and Holmes produced a method for quantifying the difference between two evolutionary trees, effectively determining the distance between them.[47] The fact that the space of phylogenetic trees has "non-positively curved geometry", particularly the uniqueness of shortest paths or geodesics in CAT(0) spaces, allows using these results for practical statistical computations of estimating the confidence level of how accurate particular evolutionary tree is. A free software package implementing these algorithms has been developed and is actively used by biologists.[47]
Selected works
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Vogtmann, Karen (1981), "Spherical posets and homology stability for On,n" (PDF), Topology, 20 (2): 119–132, doi:10.1016/0040-9383(81)90032-x, MR 0605652
Culler, Marc; Vogtmann, Karen (1986), "Moduli of graphs and automorphisms of free groups" (PDF), Inventiones Mathematicae, 84 (1): 91–119, Bibcode:1986InMat..84...91C, doi:10.1007/BF01388734, MR 0830040, S2CID 122869546
^ abcdCuller, Marc; Vogtmann, Karen (1986), "Moduli of graphs and automorphisms of free groups" (PDF), Inventiones Mathematicae, 84 (1): 91–119, Bibcode:1986InMat..84...91C, doi:10.1007/BF01388734, S2CID 122869546, archived (PDF) from the original on June 12, 2007, retrieved November 29, 2008.
^"Obituary | Anna K. Smillie (1929–2020)". Cremation Society of the Carolinas. Archived from the original on August 21, 2021. Retrieved August 21, 2021.
^Karen Vogtmann, The cohomology of automorphism groups of free groups. International Congress of Mathematicians. Vol. II, 1101–1117, Invited lectures. Proceedings of the congress held in Madrid, August 22–30, 2006. Edited by Marta Sanz-Solé, Javier Soria, Juan Luis Varona and Joan Verdera. European Mathematical Society (EMS), Zürich, 2006. ISBN 978-3-03719-022-7
^Invited Addresses, Sessions, and Other Activities. AMS 2007 Annual Meeting. Archived December 21, 2009, at the Wayback MachineAmerican Mathematical Society. Accessed November 28, 2008
^VOGTMANNFEST Archived May 5, 2018, at the Wayback Machine, conference info. Department of Mathematics, University of Utah. Accessed July 13, 2010
^List of Fellows of the American Mathematical Society Archived December 5, 2012, at archive.today, retrieved 2013-08-29.
^List of members, Academia Europaea, archived from the original on June 19, 2022, retrieved October 2, 2020
^New members, American Academy of Arts and Sciences, 2023, archived from the original on April 22, 2023, retrieved April 21, 2023
^Royal Society announces new round of esteemed Wolfson Research Merit Awards Archived April 2, 2019, at the Wayback Machine, The Royal Society press release, 09 May 2014. Accessed 14 September 2017.
^Karen Vogtmann receives Humboldt Research Award Archived January 7, 2017, at the Wayback Machine, Math Matters. Department of Mathematics, Cornell University, December 2014; p. 2
^MSRI. "Mathematical Sciences Research Institute". www.msri.org. Archived from the original on September 27, 2010. Retrieved June 7, 2021.
^7ECM Plenary Talks Archived February 2, 2019, at the Wayback Machine, 7th European Congress of Mathematics, July 18–22, 2016.
The quadrennial Congress of the European Mathematical Society. Accessed September 14, 2017
^Editorial: 7th European Congress of Mathematics Archived March 4, 2016, at the Wayback Machine, Newsletter of the European Mathematical Society, June 2015, issue 96, p. 3
^"Prizes of the London Mathematical Society" (PDF), Mathematics People, Notices of the American Mathematical Society, 65 (9): 1122, October 2018, archived (PDF) from the original on November 14, 2018, retrieved November 14, 2018
^"Royal Society elects outstanding new Fellows and Foreign Members". The Royal Society. May 6, 2021. Archived from the original on May 6, 2021. Retrieved May 21, 2021.
^"2022 NAS Election". www.nasonline.org. Archived from the original on May 10, 2022. Retrieved May 22, 2022.
^Karen Vogtmann, Spherical posets and homology stability for . Archived February 15, 2017, at the Wayback MachineTopology, vol. 20 (1981), no. 2, pp. 119–132.
^Farb, Benson (September 12, 2006). Problems on Mapping Class Groups and Related Topics. American Mathematical Soc. p. 335. ISBN 978-0-8218-3838-9.
^Karen Vogtmann, Automorphisms of free groups and Outer space. Archived May 24, 2024, at the Wayback MachineGeometriae Dedicata, vol. 94 (2002), pp. 1–31; Quote from p. 3: "Peter Shalen later invented the name Outer space for Xn".
^Bestvina, M.; Feighn, M.; Handel, M. (1997). "Laminations, trees, and irreducible automorphisms of free groups". Geometric and Functional Analysis. 7 (2): 215–244. doi:10.1007/PL00001618.
^Gilbert Levitt and Martin Lustig, Irreducible automorphisms of Fn have north-south dynamics on compactified Outer space. Journal of the Institute of Mathematics of Jussieu, vol. 2 (2003), no. 1, 59–72
^Levitt, Gilbert; Lustig, Martin (2008), "Automorphisms of free groups have asymptotically periodic dynamics", Crelle's Journal, 2008 (619): 1–36, arXiv:math/0407437, doi:10.1515/CRELLE.2008.038
^Guirardel, Vincent (May 2000). "Dynamics of Out(Fn) on the boundary of outer space". Annales Scientifiques de l'École Normale Supérieure. 33 (4): 433–465. doi:10.1016/S0012-9593(00)00117-8.
^Hatcher, Allen; Vogtmann, Karen (1998). "Cerf Theory for Graphs". Journal of the London Mathematical Society. 58 (3): 633–655. doi:10.1112/S0024610798006644.
^Hatcher, A.; Vogtmann, K. (2004). "Homology stability for outer automorphism groups of free groups" (PDF). Algebraic and Geometric Topology. 4 (2): 1253–1272. doi:10.2140/agt.2004.4.1253.
^James Conant, and Karen Vogtmann.
On a theorem of Kontsevich. Archived January 25, 2022, at the Wayback Machine Algebraic and Geometric Topology, vol. 3 (2003), pp. 1167–1224
^Conant, Jim; Vogtmann, Karen (2003). "Infinitesimal operations on complexes of graphs". Mathematische Annalen. 327 (3): 545–573. arXiv:math/0111198. doi:10.1007/s00208-003-0465-2.
^James Conant, and Karen Vogtmann, Morita classes in the homology of automorphism groups of free groups. Archived April 29, 2022, at the Wayback MachineGeometry & Topology, vol. 8 (2004), pp. 1471–1499
^ abJulie Rehmeyer. A Grove of Evolutionary Trees. Archived February 27, 2012, at the Wayback MachineScience News. May 10, 2007. Accessed November 28, 2008