Magma is a computer algebra system distributed by the University of Sydney, and designed for solving problems in algebra, number theory, geometry and combinatorics.

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Output for places in Magma's online calculator

I'm using Magma's online calculator to study some algebraic fuction fields, places, etc. I know that for an algebraic function field $F/K$, the places $\mathbb{P}_F$ are principal ideals of the ...
2
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2answers
49 views

Help finding a summation using CAS

While approximating an integral by midpoint rule, I ended up with $$\iint_R f(x, y)\hspace{1mm}dA\approx \dfrac{1}{n^2}\sum_{i=0}^{n-1}\sum_{j=0}^{n-1} f\left[\dfrac{1}{2n}+\dfrac{i}{n},\hspace{3mm} ...
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1answer
52 views

schur index in GAP

What is the command for the Schur index in GAP? Let $χ$ be an irreducible (complex) character of a finite group, $G$. The Schur index $m_K(χ)$ of $χ$ over the field $K$ is the smallest positive ...
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1answer
42 views

Character Table of Finite Group In Magma

I want to get character table of following group for some $n$ with MAGMA $$G\langle a,b\rangle := \mathrm{Group}\langle a,b\mid a^{2n}, b^4, b*a*b*a, b^{-1}*a*b^{-1}*a\rangle;$$
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19 views

Changing the “Type” of an object in Magma

The computer algebra system Magma can store groups as one of many different types. For example, using AbelianGroup([2,2]) we obtain the Klein $4$-group stored as type GrpAb. However, we can also ...
2
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1answer
50 views

MAGMA Commands for Galois Theory calculations

Perhaps this is walking over old ground (or the wrong place to ask this), but I'm looking to use MAGMA to perform certain calculations in Galois Thoery. The motivation of this question is to create an ...
0
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1answer
38 views

Magma error: User error: Imported environment value 'z' cannot be used as a local

Can anyone figure out how to fix this error? I want to define z beginning as 1 and update z to 2z everytime. Basically I was z = 1, 2, 4, 8, 16, .... z := 1; Successive := procedure(x1,y1,d); ...
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2answers
99 views

calculate structure automorphism group in MAGMA

Please hint me! Is there any instruction in MAGMA to calculate structure automorphism group by using generators? for example: ...
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2answers
324 views

Embedding as a subgroup

Suppose I am given two finite groups $G$ and $H$ (not too large: let's say their orders are around $10000$ and $100$ respectively, and the order of $H$ divides the order of $G$). These may be ...
2
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2answers
98 views

Does the Windows version of MAGMA have a memory limit?

Sorry if this isn't the best place to ask support type MAGMA questions, but I haven't found a single forum or anything for MAGMA users to talk. I have access to a copy of MAGMA which is running on a ...
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2answers
58 views

Computing $-\frac{655}{8}$ modulo 35 efficiently in Magma (CAS)

Modexp$(-81.875,1,35);$ will not work. So what I have to do is the following: Modexp$(-81,1,35); = 24$ $875/1000; = 7/8$ Modexp$(24*7,1,35); = 28$ Modexp$(8,-1,35); = 22$ Modexp$(22*28,1,35); = ...
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1answer
62 views

Expressing a matrix in terms of subgroup generators using Magma

With Magma, it is possible to define a subgroup $H$ of a finite matrix group $G$ in terms of generators. Given a matrix $M\in G$, Magma can also determine whether $M\in H$. Presumably, if Magma ...
3
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0answers
53 views

Adjoint action of a Lie algebra in MAGMA

Let's say I have a Lie algebra $L$ and an element $x$ in $L$. I need to compute $(\mathrm{ad} \ x)^n(y)$ for several values of $y$ and a particular value of $n$. I thought the best way to do this ...
0
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1answer
70 views

Computing the analytic $p$-adic $L$-function via modular symbols in MAGMA

I need to compute the analytic $p$-adic $L$-function of an elliptic curve at a prime $p$ via modular symbols using MAGMA. In ...
0
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1answer
44 views

Printing long lines in MAGMA without line break

In MAGMA, how do I print a long list of items to a file without automatic line breaks? It seems to me that there is an internal length limit and anything longer than it will result in a automatic ...
2
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2answers
178 views

Galois group command for Magma online calculator?

I need to test if a family of 7th deg and 13 deg equations are solvable. I'm new to Magma, so my apologies, but what would I type in, http://magma.maths.usyd.edu.au/calc/ to determine the Galois ...
4
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1answer
91 views

Reading a Character Table in Magma

These are the outputs of two character tables from Magma. The first is for $A_5$. The second is for $GL_3(2)$. What is the significance of the '$+$' and '$0$' symbols? I can produce more tables if ...
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0answers
28 views

Coercing a vector into a module in MAGMA.

Given a $1\times n$ row vector $v$ over a ring $R$, and an $n$-dimensional $R$-module $M$, is there any way to coerce the vector $v$ into $M$ (the obvious $M!v$ does not work).
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110 views

Representing Points of Jacobian in Magma

Although I understand the Mumford representation of points on the Jacobian (of a genus 2 hyperelliptic curve), I don't understand how Magma represents such points. I would guess the confusion arises ...
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33 views

Revealing output slowly in Magma

When working in Magma, is there a command to gradually reveal the output. For example, if you have a finite group $G$ and you want to calculate SubgroupLattice(G), then the output may be thousands of ...
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1answer
65 views

MAGMA: Retaining original vertex set

I am trying to work with graphs in MAGMA, but to my surprise I noticed that the vertices of the graph are no longer considered elements of the set I started with. Here is an example: X:={1.. 13}; ...
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2answers
131 views

Finding all finite field embeddings

Does there exist an efficient (i.e. sub-exponential) algorithm for finding all possible embeddings of one finite field into an isomorphic field? I'm particularly interested in ways to embed ...
2
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1answer
67 views

Producing a set of matrices in MAGMA

As part of my work I need to define the set of all $n\times n$ matrices with entries in $\{0,1,\ldots,n\}$ (considered as a subset of $\mathbb{Z}$), such that each row and column of the matrix sums to ...
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1answer
48 views

How embeding the direct product of permutational groups in $S_n$ using the Magma?

I would like embedding the direct product $Sym(\{1,2,3\} ) \times Sym(\{4,5,6\}) \times Sym(\{7,8\})$ in $Sym(8)$ using the software Magma. Anyone can help me?
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1answer
42 views

a codeword over $\operatorname{GF}(4)$ -> two codewords over $\operatorname{GF}(2)$ using MAGMA

A codeword $X$ over $\operatorname{GF}(4)$ is given. How can I write it as $X= A+wB$ using MAGMA? where $A$ and $B$ are over $\operatorname{GF}(2)$ and $w^2 + w =1$. Is there an easy way, or do I have ...
0
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1answer
86 views

changing the column order of a matrix using MAGMA (software)

I've just begun to use Magma (software). I have several questions. I am trying to change the columns of a 9x18 matrix according to Random(Sym18). the Random gives me a permutation like ...
3
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1answer
286 views

Programmatically solving a system of nonlinear equations over GF(2)

I have the following relatively large system of nonlinear equations over $GF(2)$: $ 0 = w7x7 + w7x5 + w7x4 + w7x0 + w6x6 + w6x5 + w6x1 + w5x7 + w5x6 + w5x2 + w4x7 + w4x3 + w3x4 + w2x5 + w1x6 + w0x7 ...
2
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2answers
443 views

Why is this curve nonsingular?

Let $C$ be the projective closure of $Z(f) \subset \mathbf{A}^2$ where $f$ is an irreducible polynomial of degree 4 in $x$ and degree 2 in $y$, so $C = Z(f^*) \subset \mathbf{P}^2$ where $f^*$ is the ...
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1answer
88 views

Getting the multiplication table in Magma

I have described a group in Magma by specifying a presentation: ...
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1answer
69 views

Group representation in MAGMA

I worked with MAGMA online and studied the handbook, but I still do not know how to print the Cayley table. It is possible to print the elements, but the representation is somewhat unuseful. It ...
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0answers
79 views

Efficiency of Group-Theoretic Algorithms in MAGMA

Given a finite permutation group $G$ and an element $a\in G$ with conjugacy class $X$, I am interested in determining when for a given element $x\in X$ the subgroup $<a,x>$ generated by $a$ and ...
3
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1answer
273 views

Dimension of a certain quotient ring of $\mathbb{C}[x_0,\ldots,x_{m-1}]$.

Let $A=\mathbb C[x_0,\dots,x_{m-1}]$ be the polynomial ring on $m$ variables. Define $X(u)=\sum_{i=0}^{m-1} x_i u^{i+1}$ and denote by $(X(u)^r)_n$ the coefficient of $u^n$ in the expansion of the ...
2
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1answer
151 views

Character table in MAGMA

Below is a character table created using the MAGMA computer algebra system. What is the meaning of the rows starting with $p=2$, $p=3$, etc.? I've tried looking in the documentation, but couldn't ...
4
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1answer
253 views

MAGMA question: SemidirectProduct using a homomorphism $f:G \rightarrow GL_n(\mathbb{F}_p)$.

Suppose I have a homomorphism $f:G\rightarrow GL_n(\mathbb{F}_p)$ and I wish to form the semidirect product $E\rtimes_f G$ with $E$ being the elementary abelian group of order $p^n$. The Semidirect ...
2
votes
1answer
296 views

Binary notation in Magma

As a part of programming an Elliptic Curve Method with montgomery coordinates in Magma, I need to have an algorithm to convert a number from decimal notation to binary notation. Since there is no ...
2
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2answers
99 views

Coercion in MAGMA

In MAGMA, if you are dealing with an element $x\in H$ for some group $H$, and you know that $H<G$ for some group $G$, is there an easy way to coerce $x$ into $G$ (e.g. if $H=\text{Alt}(n)$ and ...
3
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2answers
278 views

How do I break MAGMA? [closed]

Is there any way I can break and get back to the prompt in MAGMA when MAGMA is spending forever doing some computation? I don't wan't to Ctrl-D, because then I will lose all sorts of stored variables, ...
0
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1answer
116 views

How to iterate over power set in MAGMA?

I want do something for all subsets J of a certain cardinality of {1,2,...,n}, for a (previously declared) number n. It seems magma is not happy with: for J in PowerSet([1..n]) do To which MAGMA ...
2
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1answer
104 views

Picking out columns from a matrix using MAGMA

How do I form a new matrix from a given one by picking out some of its columns, using MAGMA?
3
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2answers
308 views

Learning to use MAGMA

I'm trying to learn to use MAGMA for research in group theory, but it's been slow going. I've been using the MAGMA handbook provided online, but it's rather hard to learn with. I feel like it's hard ...
3
votes
1answer
208 views

CAS: Computing homology of complex of non-free abelian groups

Which computer algebra system allows me to compute the homology of a complex of finitely presented abelian groups which are not necessarily free? Sage and Magma apparently don't: see here and here. ...