Linked Questions

39 votes
6 answers
6k views

Who invented diagrammatic algebra?

There is a strong and growing trend to do mathematics via diagrammatic algebra, which involves constructing and manipulating equations whose elements are diagrams drawn in the plane. The manipulations ...
Daniel Moskovich's user avatar
49 votes
4 answers
6k views

How to constructively/combinatorially prove Schur-Weyl duality?

How is Schur-Weyl duality (specifically, the fact that the actions of the group ring $\mathbb{K}\left[ S_{n}\right] $ and the monoid ring $\mathbb{K}\left[ \left( \operatorname*{End}V,\cdot\...
darij grinberg's user avatar
10 votes
4 answers
2k views

Quotient space of $\mathbb{C}^5$ under the action of $SL(2,\mathbb{C})$

One sees that given the $SL(2,\mathbb{C})$ action on $\mathbb{C}^5$, thought of as the space of polynomials of the form, $$a_0 x^4 + 4a_1 x^3 y + 6a_2x^2y^2 + 4a_3xy^3 + a_4 y^4$$ the ring of ...
Anirbit's user avatar
  • 3,541
6 votes
3 answers
1k views

Product of the entries of a matrix

Given a $n \times n$ matrix $A = (a_{ij})$, I was wondering if there was any theory or research interest relevant to the term $$ \prod_{i,j} a_{ij}$$ the product of all the entries of the matrix.
user135520's user avatar
11 votes
3 answers
861 views

Nonnegativity of an integral over the unitary group

For an $n$-by-$n$ unitary matrix $U$ and a permutation $\sigma\in S_n$, let $$w_\sigma=(-1)^\sigma\det(U^*)\prod_{i=1}^n U_{i,\sigma(i)}.$$ Is $\int_{U(n)}\mathrm{Re}(w_{\sigma_1})\mathrm{Re}(w_{\...
MTyson's user avatar
  • 1,593
20 votes
1 answer
1k views

Symmetric polynomial from graphs

Let $g$ be a directed, connected multigraph, on $n$ vertices, without loops. Define $$P_g(x_1,\dots,x_n) := Sym\left[ \prod_{(i,j) \in g} (x_i-x_j) \right]$$ where $(i,j)$ is the directed edge ...
Per Alexandersson's user avatar
19 votes
2 answers
1k views

Explicit invariant of tensors nonvanishing on the diagonal

The group $SL_n \times SL_n \times SL_n$ acts naturally on the vector space $\mathbb C^n \otimes \mathbb C^n \otimes \mathbb C^n$ and has a rather large ring of polynomial invariants. The element $$\...
Will Sawin's user avatar
  • 148k
18 votes
1 answer
1k views

Why should algebraic geometers and representation theorists care about geometric complexity theory?

Geometric complexity theory has demonstrated that complexity theorists should care about algebraic geometry and representation theory, but, why should algebraic geometers and representation theorists ...
Trent's user avatar
  • 989
8 votes
1 answer
987 views

Steps in Geometric Complexity Theory

GCT purports to provide a program to show that $NP \not \subset P/poly$. At the high level what are the steps involved in the program and what stage is each step in? What difficulties currently are ...
Turbo's user avatar
  • 13.9k
9 votes
2 answers
718 views

Generalization of Pascal's theorem to higher dimensions

Pascal's celebrated theorem in classical geometry gives a necessary and sufficient condition for the existence of a conic through six given points in the plane. Does there exists a similar statement ...
Mostafa - Free Palestine's user avatar
9 votes
1 answer
506 views

Current state of the art in geometric complexity theory

I came across this interesting question from almost 7 years ago: What are the current breakthroughs of Geometric Complexity Theory? My question is quite simple: Have there been any breakthroughs in ...
Bobby-John Wilson's user avatar