A computer algebra system (CAS) is a program which is able to carry out various symbolic manipulations with mathematical expressions. Some well-known computer-algebra systems: Mathematica, Maple, Wolfram Alpha, GAP. For questions about Mathematica please see the ...

learn more… | top users | synonyms

1
vote
2answers
265 views

Plotting parametric equations in Maple

I have the following problem. Let $\alpha:=\alpha(v)$ and $\beta:=\beta(v)$, where $v\in\mathbb{R}$. Using MAPLE, I would like to plot $\alpha$ and $\beta$ in the $(\alpha,\beta)$ space as $v$ varies ...
1
vote
1answer
87 views

Computing Resultant

The resultant of two polynomials is defined as the determinant of the Sylvester matrix. If the polynomials are of degree $n$ and $m$, than the Sylvester matrix will be of dimension $(m+n)\times ...
1
vote
1answer
114 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
vote
1answer
52 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
1answer
69 views

How to test a formula online?

I have an equation I have devised, it is: $$\frac{H+O}{25}+\frac{D}{12970}+\frac{E}{363}+110 = X$$ The equation doesn't matter, I just posted it as an example. I need to be able to plug in values ...
1
vote
1answer
227 views

How to effectively compute a periodic function?

I'm writing a program to compute a value of periodic function for any arbitrary large argument: $f(k) = (\sum_{n=1}^{2^k} n)\mod\ (10^9 + 7)$, where $n,k \in \mathbb{N} $ I know that $ f(k + P) = ...
1
vote
1answer
74 views

Is there CAS design wisdom regarding categorizing expressions?

Is there CAS design wisdom regarding categorizing expressions? For instance. A user types in the expression $X^2 + X + 1$. Would it be best to classify it as a member of $R[X]$ (for some R, yet to ...
1
vote
1answer
15 views

Prevent Maple to evaluate before simplify a function

I have been trying to find a domain of $f(x)=\frac{x}{\frac{(x+2)}{(x-3)}}$ using different kind of software ( its clear the domain of this function is $\mathbb{R}\backslash \{-2,3\}$ ). When I tried ...
1
vote
0answers
12 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 ...
1
vote
1answer
17 views

In SAGE, what function factors a polynomial whose coefficients are parameters?

In SAGE the function "factor" will factorize elementary polynomials with coefficients in $\Bbb Q$. For example: x,y = var('x,y') poly = x^3-y^2*x factor(poly) SAGE: x*(x-y)*(x+y) ...
1
vote
0answers
31 views

How does one solve equations over finite fields in SAGE?

Sage has the method solve (or function, I'm not sure what's the correct terminology) that finds solutions to 'symbolic expressions'. In particular, if one wants to find solutions for a given set of ...
1
vote
1answer
34 views

Help in understanding risch algorithm

This is an excerpt from the paper that explains risch algorithm for symbolic integration. I do not understand how do we get to the residue directly and also how does it help us in the integration. ...
1
vote
0answers
188 views

Solving large, sparse system of linear equations

I have a system of linear equations as follows: $$(A+I)x=B$$ where $I$ is the $n\times n$ identity matrix, $A$ is a $n\times n$ matrix such that the first and last rows are blank, and, for every ...
1
vote
0answers
13 views

Tools for optimizing asymptotic bounds.

Is there any tool for this task ? Given the asymptotic bound in term of $n$ and other paramaters $t_1,\dots,t_r$, then return the value for each $t_i$ which optimizes the expression in term of $n$, ...
1
vote
0answers
70 views

How to solve an equation in three variables fixing two of the variables?

Also, I have the following equation, I want to solve it for $b$ keeping $a$ and $c$ fixed. $5b^5+(60-5a)b^4+(125+50c-80a)b^3+(594c-445a-775)b^2+(2324c-1005a-3270)b+3000c-750a-3000=0.$ Also how to ...
1
vote
0answers
86 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 -- ...
1
vote
0answers
63 views

Looking for a binomial system solver

I am interested in solving binomial systems of the form $$ \begin{cases} a_1 x_1^{d_{11}} x_2^{d_{12}} \cdots x_n^{d_{1n}} + b_1 x_1^{d_{11}} x_2^{d_{12}} \cdots x_n^{d_{1n}} &= 0 \\ ...
1
vote
0answers
37 views

CAS for counting points of varieties over finite fields

I am looking for a computer algebra system, which is able to some of the following (in theory equivalent) things for a smooth projective variety defined over a finite field: -Count the number of ...
1
vote
0answers
669 views

Simple example application of Karush-Kuhn-Tucker conditions to minimization problem

I am wondering if there is a simple example application of the Karush-Kuhn-Tucker conditions to show that a minimum exists for a multivariate minimization/optimization problem. Could anyone suggest a ...
1
vote
1answer
41 views

Interpreting a chain of m's and o's from Macaulay2

This has been crossed referenced here as well in case a software developer understands this language. I am using Macaulay2 and does anyone know how to read the following? Example 1: -- ...
1
vote
0answers
133 views

How do mathematicians handle functions of functions that may change?

E.g. let $f(x) = $ some function. Now define $h(x) = f(g(x))$. Now suppose the definition of $g(x)$ changes around in a discussion. Do we still refer to $h(x)$ as the original $h(x)$ or only when ...
1
vote
0answers
60 views

Computing relations on the columns of a matrix

Given an $m\times n$ (with $n>m)$ matrix $M$ over a polynomial ring $R=k[x_1,...,x_n]$, suppose that every column of $M$ is an $R$-linear combination of $m$ specified columns. I would like to ...
0
votes
1answer
139 views

The mathematics underlying this baroque expression of the double-factorial

On the OEIS page for the double factorial, there are three ways of getting the sequence in PARI. One of them is this curious bit of PARI code: ...
0
votes
1answer
62 views

Postfix notation in MAPLE

I usually use MATHEMATICA as a computer algebra system and there I heavily employ the postfix notation (achieved by "//" at the end of some command), e.g. ...
0
votes
1answer
92 views

Semi directProduct and Maximal subgroup in gap [closed]

Let $P$ be a quaternion of order 8 and $Q$ a cyclic group of order 9 and $G=[p]Q$, a semidirect product ($P$ is normal in $G$). Let $M$ be a maximal subgroup of $G$ such that $Q<M$. I want to ...
0
votes
1answer
36 views

Solving an equation in charcateristic 2 in sage OR finding 3-torsion points of an elliptic curve over field with char 2

Problem: show that an elliptic curve over a field of char 2 has nontrivial 3-torsion points Method: I used SAGE to unwind the duplication formula for an elliptic curve given in short Weierstrass form ...
0
votes
1answer
79 views

Symbolic manipulations of integral equations

I was trying to learn about solving integral equations using symbolic algorithms. After a quick web search, I mostly found items like this Mathematica journal article that mostly focuses on how to use ...
0
votes
2answers
70 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 ...
0
votes
1answer
2k views

Plot Y-Range on Mathematica

I have a plot that I would like to slightly manipulate in Mathematica. Here is the code I am entering: Plot[{x, 2^x, log_2(x)}, {x, -1, 3}] As you can see $x$, $2^x$, and $log_2(x)$ are all ...
0
votes
2answers
104 views

Simplify basic expression

Please, does anyone know which tool can simplify expressions like: $$a^4 - 4a^3b + 6a^2b^2 - 4ab^3 - a + b^4$$ into: $$(a - b)^4 - a$$ I tried SymPy, Maxima and W|A without success. PS: I'm ...
0
votes
1answer
29 views

Canonical Separation of variables

Do the functions of the form $\psi(x)\phi(y)$ span $L^2(\mathbf{R}^6)$? Insert proper grammar here.
0
votes
1answer
26 views

software with a routine for the vanishing ideal of a finite set of points

I am looking for an algebraic software package that provides a routine that computes the vanishing ideal of a finite set of points. So far i am working with Macaulay2 but i have not been able to find ...
0
votes
1answer
84 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 ...
0
votes
1answer
219 views

Problems Using Wolfram Alpha

I've always had some problem with the usage of wolfram alpha.It computes simple derivates, integrals and solves simple linear and quadratic equations flawlessly.It seems to me that it ignores step by ...
0
votes
1answer
425 views

Maple: How to turn a set of vectors into a matrix?

In Maple the command NullSpace turns a given matrix into a set of vectors -- a basis for its null space. This is precisely what it should in a mathematical sense. However, for computations using the ...
0
votes
0answers
16 views

Mathematica: Extract the piece that contains x=0 from within a piecewise function [migrated]

In mathematica, I have a piecewise function similar to: Piecewise[{ {x^2 + 2*x - 4, 0 <= x <= 1/4}, {0, true} }] I don't ...
0
votes
0answers
42 views

Todd-Coxeter algorithm: coincidences

I'm trying to understand the Todd-Coxeter algorithm with the help of a multiplication and relator table, but there is one thing about coincidences that is not really clear. For some small groups (for ...
0
votes
0answers
56 views

Why are these CAS calculated integrals equal

I let Wolfram evaluate this integral: $$\int\frac{-2\sin(x)\cos(x)}{2\cos^2(x)+\cos(x)-1}dx$$ 1st result from WolframAlpha online was $$\frac43 \log(\cos(\frac{x}2))+\frac{1}{3\log(1-2 \cos(x))}+C$$ ...
0
votes
0answers
22 views

Graded piece of ring in Macaulay2

I apologize for the basic question, but I couldn't figure how to do this. I'm looking at the homogenous ring $R = QQ[w,x,y,z]$, I take $I = ideal(w*z-x*y)$ and $S=R/I$. Then I construct some ideal $J$ ...
0
votes
0answers
31 views

Silverman exercise 3.1 proving that two polynomials are relatively prime iff the discriminant is non-zero

Silverman, p. 104: Show that the polynomials $$f=x^4−b_4x^2−2b_6x−b8 \qquad \text{and}\qquad g=4x^3+b_2x^2+2b_4x+b_6$$ appearing in the duplication formula (III.2.3d) are relatively prime if ...
0
votes
1answer
33 views

Computing univariate resultant via modified Euclidean algorithm

In an answer to the question Resultant of Two Univariate Polynomials, a PDF of course slides was linked which describes a modification of Euclid's algorithm for computing univariate polynomial ...
0
votes
1answer
57 views

How to get 2 percentages to a 100%

First of im new to this site and I've never been the sharpest at math, im a web developer by trade. My question is math related but ill just give you a quick background about my website so that you ...
0
votes
0answers
25 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 ...
0
votes
0answers
25 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).
0
votes
0answers
32 views

Can Maple solve recurrence relations when n is only certain numbers?

If you have an equation $a(n)=a_{n-1}+2a_{n-2}$ only defined when n is powers of 2, how would convey that to Maple that n has a restriction? What if you wanted only $n \ge 2$?
0
votes
0answers
24 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 ...
0
votes
0answers
52 views

R code for triple integration

I am trying to write R code for triple integration. Here, I am just using a simple function as an example: f(x,y,z) = x^2*y+z. Here's what I have : fvec = function(x,y,z) sapply(x, function(t,y,z) ...
0
votes
0answers
32 views

Evaluating polynomials at elements of algebras in Magma

I've defined a $2$ dimensional algebra, $A$ in Magma as follows: R:=FieldOfFractions(PolynomialRing(GF(2),10)); A:=Algebra< R,2|[1,0,0,1,0,1,1,1]>; The sequence of $1$'s and $0$'s just ...
0
votes
0answers
25 views

Picking out Vector Coefficients in Magma

Suppose $K/k$ is a finite field extension, with fixed basis $e_1,\ldots,e_d$, and $f\in K[x_1,\ldots,x_n]$. Using our basis, $f$ has a unique expression as a sum of polynomials in ...
0
votes
0answers
28 views

How to use computer software for q-series calculations?

I have been reading about the dissections of cranks and there are lot of calculations with q-series identities which are very tedious by hand. What kind of computer algebra packages can we use in ...