1
vote
1answer
41 views

If $A\ne 0$ is a square matrix over a commutative ring with $\det A=0$, then its null space contains an element whose components are minors of $A$

Let $R$ denote a commutative ring and $A\ne 0$ a $n\times n$ matrix over $R$ with $\det A=0$. Then there exists a $x\in\ker A\setminus\left\{0\right\}$ such that all components of $x$ are minors of ...
1
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2answers
48 views

Some questions about similar matrices

Two matrices A and B are similar, if and only if there exists an invertible matrix C with $A=C^{-1}BC$. A necessary condition for the similarity is, that the characteristic polynomials coincide. I ...
3
votes
0answers
63 views

Computing the decomposition of a representation of $S_n$

I have an explicitly defined representation of the symmetric group that I would like to decompose into irreducibles. How to do this most easily? The best approach I have so far is as follows: Find a ...
3
votes
1answer
1k views

Using Wolfram Alpha to solve a system of linear equations

How do I input the below system of equations in Wolfram Alpha in order to solve for the unknowns? I'm wondering if there's some kind of code that can be written in order to make wolfram alpha ...
2
votes
1answer
107 views

How to extract the indeterminates from a set of polynomial?

I am a biologist and I am facing a huge problem. I would like to extract the indeterminates of a set of polynomials, for example, I have: $f_{1} = \{\\x_{3}^{2} + x_{1}*x_{2} + x_{1} + x_{1}*x_{3},\\ ...
5
votes
2answers
460 views

What free software can I use to solve a system of linear equations containing an unknown?

Question: What free software can I use to solve a system of linear equations $M\mathbf{x}=\mathbf{y}$ where the entries of $\mathbf{y}$ vary with an unknown quantity $n$? Presumably I could do ...
1
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1answer
132 views

Computing Invariant Subspaces of Matrix Groups

Does anyone have a program written in Mathematica (or SAGE or GAP) that computes the invariant subspace lattice of a matrix group?
1
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1answer
54 views

What are the explicit expression for this interpolation problem

We want to fit $f(x) = a_0 + a_1 *x + a_2 * x^2 + ... + a_n * x^n$ to the data $(x_i,f(x_i))$ for $i = 0 ... n.$ It will give rise to the following system $ A a = b $ Here $ a = [ a_1 a_2 a_3 ...
1
vote
0answers
88 views

Flatten kronecker product in CAS?

I am a new user of Maxima, and I need to trace the elements of a big messy kronecker product of symbolic matrices. I tried the following to get my feet wet, but I don't get a simple, flat matrix -- ...
0
votes
2answers
71 views

solving a matrix equation $X-I=a \cdot (X\cdot U^T + U \cdot X)$

I am trying to solve the $n \times n$ diagonal matrix $X$ in the following equation: $$X-I=a \cdot (X\cdot U^T + U \cdot X)$$ where $0<a<1$ is a given scalar, $U$ is a $n \times n$ given ...
4
votes
2answers
14k views

Using Wolfram Alpha For Solving A System Of Equations

How do i input the below system of equations in wolfram alpha in order to solve for the unknowns and plot them? If i just say "solve" and input these equations one after the other with a simicolen ...