Joseph (JM) Landsberg

Owen professor of mathematics

Office: Blocker 601H
Office hours:  Tues. 10-11am, Thurs. 2-3pm or by appointment
E-mail: jml@math.tamu.edu
TAMU math dept homepage
Supported by NSF grant CCF-2203618

Teaching Fall 2024:

Algebraic geometry I

MWF 11:30-12:20 BLOC 110

Spring 2025: Algebraic Geometry II

Fall 2025 I am co-organizing a semester program: Complexity and Linear Algebra
at the Simons Institute UC Berkeley

Upcoming event: Symmetries and Singularities in Texas 1/31/25-2/2/25

Recent distinctions:

Spring 2022 and 2023: Chaire d'excellence (visiting endowed professorship) U. Toulouse

Research: Geometric questions originating in theoretical computer science, Algebraic geometry, differential geometry, Exterior differential systems, Homogeneous varieties,  (Click here for a summary of my research.)

I organize and co-organize:
Geometry seminar, meeting Mondays 3-4pm and Fridays 4-5pm BLOC 302.
Working seminar for post-docs and graduate students meeting   Mondays 4-5:30pm BLOC 628
Random Tensors, meeting Wednesdays 3-4pm Bloc 624



Everyone is welcome to the seminars, graduate students
are particularly encouraged to attend.
TAMU seminar calendar
My CV (last updated 6/24)
Brief biographical sketch (updated 11/23)
My  travel plans



I am on the editorial board of Foundation of Computational Mathematics,    SIGMA, and  Linear Algebra and its Applications.  

 

Papers/preprints are all on arXiv

Recent Papers  with supplementary files:

• Bad and Good news for Strassen's laser method: Border rank of the 3x3 permanent and strict submultiplicativity (with A. Conner and H. Huang) supplementary files
• New lower bounds for matrix multiplication and det_3 (with A. Conner and A. Harper) supplementary files.
• Kronecker powers of tensors useful for Strassen's laser method (with A. Conner, F. Gesmundo, and E. Ventura) supplementary files
• On the complexity of the permanent in various computational modes (with C. Ikenmeyer, JPAA 2017) ancillary files for the computational models paper: 6x6, 7x7, 8

Survey articles

Algebraic Geometry and Representation theory in the study of matrix multiplication complexity and other problems in theoretical computer science
The complexity of matrix multiplication: developments since 2014.Extended abstract of 2018 Oberwolfach Complexity meeting plenary lecture
A very brief introduction to quantum computing and quantum information theory for mathematicians
An introduction to Geometric Complexity Theory (Newsletter of the EMS 3/16)
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
      
  Books:
Quantum Computation and Information: a mathematical introduction.  AMS GSM   243.

Tensors: Asymptotic Geometry and Developments 2016–2018  CBMS Regional Conference Series in Mathematics  Vol:132

Geometry and complexity theory: Cambridge University Press studies in advanced mathematics 169.       Click here to see a draft copy

Tensors: Geometry and Applications.
         AMS GSM 128.  Click here for corrections and additions

Cartan For Beginners: Differential geometry via moving frames and exterior differential systems,
Second Edition (with T. Ivey) AMS GSM 175


Slides of recent talks:
IPAM lectures 2021: tutorial 1, tutorial 2, clay lecture 1, clay lecture 2, clay lecture 3
Efficient matrix multiplication (ILAS, Rio de Janiero, 7/19)
On The geometry of matrix multiplication (AMS sectional, Vanderbilt 4/18)
Symmetry versus Optimality (SIAM-AG, Atlanta 7/17)
Complexity theory and geometry (Berlin Mathematical School colloquium 2/15)
Perm v. det: an exponential lower bound assuming symmetry (Innovations in Theoretical Computer Science 1/16)

math reviews of all published papers


PhD students:
Current students:     Phillip Speegle, Derek Wu, and Zijin Xiao,

Graduated students:

Chia-Yu Chang,  2024 Border subrank of tensors

Arpan Pal, 2023 Concise tensors of minimal border rank

Runshi Geng, 2023,

CLASSIFICATION OF TRIPARTITE TENSORS WITH SMALL GEOMETRIC RANKS

Kashif Bari, May 2021, On the structure tensor of sl_n

Austin Conner, May 2020 New results in the complexity of matrix multiplication,
 

Fulvio Gesmundo, May 2017, Geometry and representation theory in the study of matrix rigidity
 

Cameron Farnsworth, August 2016, THE POLYNOMIAL WARING PROBLEM AND THE DETERMINANT
 

Yonghui Guan, August 2016, EQUATIONS FOR CHOW VARIETIES, THEIR SECANT VARIETIES AND
OTHER VARIETIES ARISING IN COMPLEXITY THEORY
 

Curtis Porter, August 2016 THE LOCAL EQUIVALENCE PROBLEM FOR 7-DIMENSIONAL, 2-NONDEGENERATE CR
MANIFOLDS WHOSE CUBIC FORM IS OF CONFORMAL UNITARY TYPE,
 

Yang Qi, PhD August 2013 Geometry of Feasible Spaces of Tensors
determined defining equations for the third secant variety of a triple Segre product and closedness of tensor network states,
 

Ke Ye,   PhD August  2012, IMMANANTS, TENSOR NETWORK STATES AND THE GEOMETRIC
COMPLEXITY THEORY PROGRAM determined symmetry groups of immanents, and closedness of tensor network states,

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 varietyof 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,  Nongenericity of variations of Hodge structure for hypersurfaces of high degree,
          
    Now available: