- How are the symmetric functions expressing the fundamentals of representation theory, linear algebra and matrix multiplication?
- How are the symmetric functions expressing the fundamentals of group theory, the symmetric group and permutations?
- How are the symmetric functions relating automorphisms of lists and automorphisms of sets?
Symmetric functions
- Intuitively understand the Schur functions as the characters of the irreducible representations of the general linear groups.
- Discover a more natural way to express the Schur functions than the rim hook tableaux. Do this for both symmetric function and for the functions of the eigenvalues.
- Understand the relations of the Schur functions to the binomial theorem.
- Consider the Schur functions in terms of the Jacobi-Trudi formulas - and what it means for the eigenvalue case.
- Understand how the role of the Schur functions and rim hook tableaux depends on the characteristic k of the field.
- Understand the combinatorics underlying the map between elementary (< decreasing slack) and homogeneous (<= increasing slack) bases, especially as it works in taking the power (=) basis to define the Schur (< x <=) bases. Consider this also in the case of the eigenvalues of a matrix. We also have a foursome, perhaps: Schur - monomial - forgotten? - power. The human bases - monomial and forgotten - map to elementary and homogeneous?
- Do the six natural bases of the symmetric functions correspond to the six transformations?
- Understand the elementary symmetric functions in terms of the wedge product. And the homogeneous symmetric functions in terms of the inner product?
- In category theory, where do symmetric functions come up? What are eigenvalues understood as? What would be symmetric functions of eigenvalues?
Symmetric functions of the eigenvalues of a matrix
- Make sense combinatorially of the map between the homogeneous functions of eigenvalues in terms of words and in terms of products of Lyndon words.
- How can symmetric functions of eigenvalues model my findings about the combinatorics of orthogonal polynomials?
- How do symmetric functions of eigenvalues expand on what the trace (the sum of the eigenvalues) says about representations?
Sources
Notes
- Relate the monomial, forgotten, Schur symmetric functions of eigenvalues with the matrices {$(I-A)^{-1}$} and {$e^A$}.
- Exercise: Get the eigenvalues for a generic matrix: 2x2, 3x3, etc.
- Exercise: Look for a method to find the eigenvalues for a generic matrix. Express the solving of the equation as a way of relating the elementary functions. Are they related to the inverse Kostka matrix? And the impossibility of a combinatorial solution? And the nondeterminism issue, P vs NP?
- Think again about the combinatorial intepretation of {$K^{-1}K=I$}.
- What do the constraints on Lie groups and Lie algebras say about symmetric functions of eigenvalues.
- Vandermonde determinant shows invertible - basis for finite Fourier transform
- What is the connection between the universal grammar for games and the symmetric functions of the eigenvalues of a matrix?
- How do symmetries of paths relate to symmetries of young diagrams
Partitions, duality, tableaux
Kostka matrix
Symmetric functions of eigenvalues
- Think of the roots of a polynomial (and the eigenvalues of a matrix) as inverting it.
How is the Schur functor (and its direct sums and tensor products) related to the Young diagrams? And to Schur-Weyl duality? And what do the six bases look like? And how does it relate to the symmetric functions of the eigenvalues of a matrix?
Baez, Moeller, Trimble. Schur functors and categorified plethysm.
- Spalio 4ta, 14:00 Lietuvos laiku, skaitys pranešimą
- Edinburgh Category Theory Seminar
- Elementary symmetric functions express fermions (can't repeat indices), homogeneous symmetric functions express boson (can repeat indices). But what happens when we multiply together elementary symmetric functions {$e_i$} and {$e_j$}?
Relate Grassmannian minors to elementary symmetric functions of eigenvalues