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6 votes
0 answers
584 views

Expressing a polynomial as the determinant of a matrix of linear forms

I have heard that it's a well known result (in theoretical computer science?) that if we have a polynomial $p(t_1,\dots,t_n)$ over $\mathbb Q$, we can find matrices $M_0,\dots,M_n/\mathbb Q$ such that ...
Asvin's user avatar
  • 7,746
6 votes
0 answers
998 views

Generalized Courant-Fischer theorem

Consider some quaternionic matrix $A$. A right eigvenvalue of $A$ is a quaternion $q$ such that $Ax=xq$ for some $x\in \mathbb{H}^n$. Similarly, a left eigenvalue of $A$ is quaternion $q$ such that $...
hypercube's user avatar
  • 475
5 votes
0 answers
442 views

A reference on semisimple linear algebra

Is there any literature where the tools familiar from (multi)linear algebra are systematically transferred to the setting of semisimple modules over noncommutative rings? In fact this question is a ...
Alexander Shamov's user avatar
3 votes
0 answers
62 views

Image of the reduction of a maximal order in a central simple algebra over $\mathbb Q$

Suppose $A$ is a $n^2$-dimensional central simple algebra over $\mathbb Q$, and $O_A$ is an maximal order of $A$. Choose a finite place $p$ such that $A \otimes \mathbb Q_p \cong M_n(\mathbb Q_p)$. ...
Zhiyu's user avatar
  • 6,622
3 votes
0 answers
234 views

Hurwitz–Radon problem for $ \mathbb{Q} ^{n} $

What is the maximal number of orthogonal operators $ A _{1} , \dotsc, A _ {m} $ in $ \mathbb{Q}^{ n } $ satisfying the relations $ A_{i}^{2} = - I $ and $ A_{i}A_{j} + A_{j}A_{i} = 0 $ for $ i \neq ...
Sky's user avatar
  • 923
3 votes
0 answers
40 views

Closest generators for matrix algebra which is not semisimple

Given a collection of $n$ commuting $n \times n$ matrices $A_1, \dots, A_n \subset M_n (\mathbb{R})$ which generate a semisimple algebra $\mathcal{A}$, I am interested in finding matrices $E_1, \dots, ...
Eric's user avatar
  • 131
3 votes
0 answers
134 views

Language representation problem regarding non-commutative, non-associative algebras

Consider a sentence as a series of words with an associated set of labels that tell one how information is passed through the sentence - examples include combinatory categorical grammars or Lambek ...
East's user avatar
  • 149
2 votes
0 answers
91 views

Algorithms to find the solutions of a homogenous matrix equations for non-commutative rings

In one paper from 1980 I found a note that there are no known algorithms for solving homogenous matrix equations $x \cdot M = 0$ for matrices which elements belong to a non-commutative ring. (The non-...
Leonid Dworzanski's user avatar