Joseph (JM) Landsberg, professor of mathematics

Office: Milner 329
E-mail: jml@math.tamu.edu
TAMU math dept homepage

Office hours:  Mon. 1-2pm, Thurs. 10:30-11:30 and by appointment


Teaching Spring   2013:

Math 666:Complexity and Geometry , MWF 9:10-10:00 Blocker 161

Math 311-502:Topics in Applied Math I, MWF 10:20-11:10 Blocker 161

Education

Research Interests:  Algebraic geometry, differential geometry, Exterior differential systems, Homogeneous varieties, geometric questions originating in theoretical computer science. (Click on research interests to read more.)

 
I organize and co-organize:

Working seminar in geometry meeting Tuesdays, Milner 317, 2:15-3:30pm.

Geometry seminar, meeting Fridays 4-5pm Milner 216.

Joint geometry-string theory seminar, meeting monthly Fridays 4-5pm Milner 216

Working seminar for post-docs and graduate students meeting Thursdays, Milner 317,
2:15-3:30pm
 

Everyone is welcome to the seminars, graduate students
are particularly encouraged to attend.
TAMU seminar calendar
My CV (last updated 1/13)

My  travel plans

I am  a co-organizer of the August 19 - 23, 2013 conference
Differential Geometry and its Applications, Brno, Cech Republic, and will
be organizing a special session on geometric complexity theory there.

I am co-organizing (with J. Clelland and C. Robles) , 
July 15-19, 2013
New Directions in Exterior Differential Systems
A conference in honor of Robert Bryant's 60th birthday


Co-organizing (with P. Burgisser, K. Mulmuley and B. Sturmfels) a semeseter long program Fall 2014
Algorithms and Complexity in Algebraic Geometry
to be held at the Simons Institute for Theory of Computing, UC Berkeley.
 

Now available: Tensors: Geometry and Applications.
AMS   GSM 128. Click here to see table of contents and preface, and to order.
Click here for corrections and additions

 

I am on the editorial board of Differential Geometry and its Applications
and Linear Algebra and its Applications

RECENT PAPERS/PREPRINTS

  • Explicit tensors of border rank at least 2n-2
  • New lower bounds for the rank of matrix multiplication
  • Padded polynomials, their cousins, and geometric complexity theory (with H. Kadish, to appear in Communications in Algebra)
  • New lower bounds for the border rank of matrix multiplication (with G. Ottaviani)
  • On the third secant variety (with J. Buczynski, to appear in JAC)
  • On the geometry of Tensor Network States (with Y. Qi and K. Ye, QIC, 2012)
  • Equations for secant varieties of Veronese and other varietites (with G. Ottaviani, Annali di Matematica Pura e Applicata, 2011)
  • Fubini-Griffiths-Harris rigidity of homogeneous varieties (with C. Robles, to appear in IMRN)
  • Determinental equations for secant varieties and the Eisenbud-Koh-Stillman conjecture (with J. Buczynski and A. Ginesky, to appear in J. London Math. Soc.)
  • Hypersurfaces with degenerate duals and the Geometric Complexity Theory Program (with L. Manivel and N. Ressayre, to appear in CMH)
  • P versus NP and geometry ( J. Symb. Comp.2010,  MEGA 2009 special issue)
  • Ranks of tensors and a generalization of secant varieties (with J. Buczynski, to appear in LAA special issue on tensors)
  • An overview of mathematical issues arising in the Geometric complexity theory approach to VP \neq VNP (with P. Buergisser, L.  Manivel and J. Weyman, SIAM J. Comp. 2011)
  • Holographic algorithms without matchgates (with Jason Morton and Serguei Norine, LAA special issue on tensors 2012)
  • On the ranks and border ranks of symmetric tensors (with Z. Teitler, FOCM 2010)
  • Maple file to be read with billards article below (also click here for text version)
  • On the Debarre-deJong and Beheshti-Starr conjectures on varieties with too many lines (with O. Tommasi, Mich. Math. J. 2010)
  • Lines on hypersurfaces (with C. Robles, J. London Math. Soc. 2010)
  • On secant varieties of compact Hermitian symmetric spaces (with J. Weyman, J. Pure Appl. Alg. 2009)
  • Fubini's theorem in codimension two (with C. Robles, Crelle 2009)
  • Fubini-Griffiths-Harris rigidity and Lie algebra cohomology (with C. Robles, (Asian Math. J. 2013)
  • Geometry and the complexity of matrix multiplication (survey article, Bull. AMS 2008)
  • Generalizations of Strassen's equations for secant varieties of Segre varieties (with L. Manivel, Comm. Algebra 2008)
  • On tangential varieties of rational homogeneous varieties (with J. Weyman, Jour. LMS 2007)
  • On the ideals and singularities of secant varieties of Segre varieties (with J. Weyman,  Bull. LMS 2007)
  • Legendrian varieties (with L. Manivel, Asian J. Math 2007)
  • The border rank of the multiplication of two by two matrices is seven (JAMS 19(2006) p447-459)
  • The sextonions and E_{7 1/2} (with L. Manivel)  (Advances in Math 201(2006) p143-179)
  • A universal dimension formula for complex simple Lie algebras (with L.Manivel) (Advances in Math 201(2006) p379-407)
  • Griffiths-Harris rigidity of compact Hermitian symmetric spaces (JDG 74(2006) p 395-405.)
  • Survey articles
  • Exterior differential systems, Lie algebra cohomology, and the rigidity of homogeneous varieties (2008)
  • Differential geometry of submanifolds of projective space (2006)
  • Exterior differential systems and billiards (2006)
  • Representation theory and projective geometry  (with L. Manivel), 2004


  • math reviews of all published papers


    PhD students:

    Ke Ye
    ,   PhD August  2012, IMMANANTS, TENSOR NETWORK STATES AND THE GEOMETRIC
    COMPLEXITY THEORY PROGRAM



    Ming Yang,   PhD Sept. 2012,  On partial and generic uniqueness of block term tensor decompositions in signal processing, solving  questions originating in signal processing.
                 Luke Oeding,    PhD May 2009,     Defining equations of the variety
    of principal minors
    solved a conjecture of Holtz and Sturmfels.

               Frederic Holweck, PhD fall  04,  Dual varieties, simple singularities and simple Lie algebras
    Here is a summary of his results in English

               E. Allaud, PhD spring 03, 
    thesis: Nongenericity of variations of Hodge structure for hypersurfaces of high degree,
    published in Duke. Math. J.



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    A second year graduate text (378  pages)   published by the AMS in the Graduate Studies in Mathematics series
     . To see the table of contents, preface, and selected pages click here
    To order the book from the AMS, click here.
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      New to the area? Here are some Brazos  Valley links
     

    Various links
    tamuwebmail