Questions tagged [computational-algebra]

Computational algebra is an area of algebra that seeks efficient algorithms to answer fundamental problems concerning basic algebraic objects (groups, rings, fields, etc.). For questions about generic computer algebra systems, use [tag:computer-algebra-systems].

Computational algebra is an area of algebra that seeks efficient algorithms to answer fundamental problems concerning basic algebraic objects (groups, rings, fields, etc.), such as, for example, deciding whether two groups are isomorphic, finding the decomposition of a group element in terms of the group generators, computing the lattice of subgroups of a group, etc. (see, for example, http://maths.nuigalway.ie/deBrun6/Brooksbank/Galway-1.pdf).

Thus, computational algebra differs from computer algebra, since the latter deals with questions like carrying out symbolic manipulations with mathematical expressions (though, of course, practical implementations may overlap in some areas).

Please use these notes to distinguish between the tag for questions about generic computer algebra systems, and the tag for questions about the topics outlined above.

287 questions
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Generators of a subgroup of $SL_2(\mathbb{Z}/24\mathbb{Z})$

So I have this subgroup of $SL_2(\mathbb{Z}/24\mathbb{Z})$ which has $256$ elements. Is there a way in sage to get the list of its generators ? The "only" information I have on the group is the list of its elements. If it is not implemented in Sage…
Zorba le Grec
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Polynomial system

If there are 3 numbers $x,y,z$ satisfying $f=x+y+z=3$ , $g=x^2+y^2+z^2=5$ , $h=x^3+y^3+z^3=7$ then prove that they also satisfy $x^4+y^4+z^4=9$ but not $x^5+y^5+z^5=11$ I dont know how to tackle this to be honest, i have started trying to write…
Plom
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Algebraic description of $\frac1{x+y}$ in terms of $\frac1x$ and $\frac1y$ over finite field.

Given an $a = \frac1x$ and $b = \frac1y$, is there some algebraic way to get the value $c = \frac1{x+y}$ using $a$ and $b$ without the use of inversions. I can't seem to figure it out and it might be so easy that there are no resources I could…
s3binator
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Gauss-Seidel Convergence Criterion

The convergence criterion is $\| y^{k+1} - y^{k} \| < \varepsilon$ where $k$ is iteration number. Question 1. Is it possible to use simpler criterion $$ \max_j \left(\left | y_j^{k+1} - y_j^k \right |\right) < \varepsilon $$ where $j$ is equation…