Questions tagged [magma-cas]

Question 1

Magma can compute group cohomology $H^i(G,M)$ with $i=0,1,2$ for a finite group $G$ and a $G$-module $M$ over integers or finite fields. I am wondering does it work with modules over the additive ...

Question 2

Denote by $A_4$ the alternating group on $4$ letters, and by $\pi: A_4 \rightarrow \mathbb Z/3$ a quotient. What is the best/easiest/proper way to construct the amalgamated product $$ \{ (x,y) \in ...

Question 3

I'm a bit confused about the Mumford representation of Jacobians of hyperelliptic curves used in Magma. More precisely, I'm confused about the divisor at infinity $D_\infty$ used to represent elements ...

Question 4

Consider the non-unital ring $R := u \mathbb{F}_5 + v \mathbb{F}_5 + uv \mathbb{F}_5 = \{ ua + vb + uvc : a,b,c \in \mathbb{F}_5 \} $ where $u^2 = v^2 =0$ and $uv=vu$. Then $R$ has $125$ elements. I ...

Question 5

The small group database of the computer algebra system MAGMA has a family of finite groups called "other-dihedral group": $$ \text{OD}n := \langle a, b: a^{2^{k-1}} = b^2 = 1, b a b^{-1} =...

Question 6

I want to define a family of plane curves in MAGMA over, say, $\mathbb{G}_m$ in MAGMA (all over $\mathbb{C}$). Specifically, I want to consider the family $x^2 + y^2 + z^2 + t(xy + yz + zx)$, where $t$...

Question 7

See below my toy Magma program and the printout. Here $K$ is a global function field, a quadratic extension $K_0(u)$ of the field of rational functions $K_0={\mathbb F}_5(t)$ over the finite field ${\...

Question 8

I would like to explicitly compute the Hasse-Weil zeta function of $X_0(N)$ modulo $p$ in some examples. This is mostly for my own edification, so I'm not too worried about any particular restrictions ...

Question 9

I'm trying to use Magma to count homomorphisms from fp groups to finite (permutation) groups, and it is giving me weird answers. For example, if I construct a cyclic group, it says there are no ...

Question 10

I'm trying to evaluate the basis of a Riemann-Roch space of the divisor $G$ of the rational function field $F$ over $GF(2^{16})$ at 8 places of $F$ using Magma. When building the sequence of outputs, ...

Question 11

I am trying to find an optimal system of parameters for a graded ring using Magma. Specifically, I want to use Gregor Kemper's 1999 algorithm, which is designed for this purpose. Here is a simple ...

Question 12

I have a family of finite groups, and I want to use the compute algebra system MAGMA to evaluate certain characters of these groups at specific conjugacy classes. The CharacterTable commmand returns ...

Question 13

I want to create in MAGMA the subspace of the general linear group $\operatorname{GL}_n (\mathbb{F}_5)$ consisting of matrices with only entry $\in \{ 1, -1 \}$ in ...

Question 14

Consider the cyclotomic field $K = \mathbb{Q}(\zeta_9)$. There is a totally real subfield $K_0 = \mathbb{Q}(\alpha)$ of $K$ where $\alpha = \zeta_9 + \zeta_9^{-1}$. Let $\mathcal{O}_{K_0}$ be the ring ...

Question 15

I'm trying to write a code in magma (or sage) that given a smooth cubic surface in $\mathbb{P}^3$ and a point on the surface, it give me the ramifiaction locus (so a quartic). For writing the map I ...

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Questions tagged [magma-cas]

Compute group cohomology with $\mathbb Q/\mathbb Z$ coefficients in Magma

How to construct amalgamated product of groups in magma or gap

Issue with Magma and Mumford representation

Space of $m \times n$ Matrices with Entries from a Non-unital Ring in MAGMA

name and significance of a family of groups

Defining schemes over arbitrary rings in MAGMA

Working with places of a global function field in Magma

How to explicitly compute the Hasse-Weil Zeta function of $X_0(N)$ using Sage or Magma

Magma homomorphism search

Evaluation of Riemann Roch basis in Magma

Primary invariants on MAGMA for a graded ring

ordering of conjugacy classes in MAGMA

Creating Signed Symmetric Group in MAGMA [closed]

Computing the different of an order $\mathcal{O} \subset \mathbb{Z}[\zeta_9]$

Ramification locus of a projection

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