Topic: Tensors and multilinear algebra

Misha Kilmer develops structured matrix approximation by an invertible matrix-to-tensor transformation, tensor approximation, and a mapping back to matrix space. Different tensor decompositions yield sums of structured Kronecker products, block low-rank matrices, or combinations of both. The framework exposes latent operator structure useful for large computations, and the talk considers where randomization could help. Joint work with Arvind Saibaba at North Carolina State University.

Lior Horesh presents tensor-tensor algebra designed to retain key properties of matrix algebra while representing multidimensional correlations. An Eckart–Young-like tensor representation theorem underpins computationally feasible, provably optimal decompositions. Matrix-mimetic operations allow existing computational workflows to be adapted to tensors. Examples include tensorized neural-network structures and tensor graph convolutional networks for time-evolving graphs. The discussion concludes with tensor group symmetries and extensions to equivariant learning.

Alberto Bucci develops single-pass randomized and streaming low-rank approximation, beginning with large matrices and the strengths and limitations of streaming algorithms. The discussion extends to Tucker, tensor-train, and tree tensor-network representations. Tensor-train approximations are then incorporated into Krylov solvers, including sketched GMRES, to reduce expensive intermediate contractions. The framework is presented as applicable beyond tensor trains to other tensor-network architectures.