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Questions tagged [algebra]

Abstract manipulation of symbols. Transforming an algebraic expression into the desired form.

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2answers
305 views

Update: Calculate Tensor products and traces with Mathematica

My goal is to algebraically simplify expressions involving tensor products and taking the trace. That is, I would like to compute $\operatorname{Tr}\left( \prod_i(id+a_i \otimes b_i) \right)$, using ...
2
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0answers
221 views

Identity Matrix in symbolic Tensor Product [closed]

I am trying to simplify symbolic tensor products. E.g. ...
2
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2answers
198 views

intermediate steps of simplification of algebraic expression without evaluation [closed]

I am using MMA do do some algebra and I need to do some simplification. For example, I have the following expression $$ x^2 \left( \frac{6 \left(2 c_1 x^6+c_2\right)}{x^4} \right)-x \left( 4 c_1 x^3-\...
2
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2answers
788 views

Solving equations with subscripted variables

A student of mine tried: Solve[1/R == 1/Subscript[R, 1] + 1/Subscript[R, 2], R] which did not work. We then tried: ...
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2answers
215 views

How to make `D` apply chain rule on user-defined symbols as it does on `Dot` and `NonCommutativeMultiply`

I have my own version of Dot called mydot, and it behaves quite similar to the built-in version in that it represents the non-...
1
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0answers
80 views

How to stop mathematica from exchanging my matrices this way ? [closed]

Mathematica is exchanging the matrices i have written in a way that makes my equation doesn't make sense as the dimensions do not match anymore. I want the order of my Matrices to stay the same.
4
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2answers
133 views

How can I define operators that implement the algebra of sets?

I need to define some operators with properties like idempotence and distribution over union and intersection so that Mathematica can symbolically simplify expressions. How do I define such operators? ...
1
vote
3answers
172 views

Coefficient and Addition Formula

If I type: Coefficient[Cos[x + b], Cos[x]] I get zero. But I would like Mathematica to apply: $$\cos(x+b)=\cos x\cos b-\sin x\sin b$$ Therefore the ...
0
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0answers
86 views

Multivariate remainder of polynomial in respect to a set of polynomials

I would like to have a really fast routine that computes the so called Normal Form of a multivariate polynomial f in respect to a set of other multivariate ...
2
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1answer
574 views

Not commuting operator calculation

I am working on some operator calculation; I do not want the commutation relation. so xy ≠ yx. I found the mathematica code from https://reference.wolfram.com/language/ref/NonCommutativeMultiply....
14
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2answers
3k views

Boson commutation relations

I have tried to adapt this answer to my problem of calculating some bosonic commutation relations, but there are still some issues. The way I'm implementing the commutator is straightforward: ...
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0answers
49 views

Divide both sides of an equation by -2 [duplicate]

I have: n = Cross[{-1, 2, 2}, {2, 0, -2}]; p = {1, -1, 1}; plane = ({x, y, z} - p).n == 0 // Expand Which gives: 10 - 4 x + 2 y - 4 z == 0 I'd like to divide ...
3
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1answer
155 views

How to reduce an expression into user-defined variables?

In the following code, I define a set of matrices. Then, I define a function that calculates the commutation relation relation between these matrices ...
4
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3answers
1k views

How to find a quotient group?

Given a normal subgroup H of a (large, finite permutation) group G, knowing a set of generators for each of H and G, how to find a subgroup K of G that is isomorphic to G/H? (Using Mathematica.)
1
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0answers
62 views

Algebraic equation with 4 components [closed]

I need help solving: $x^{3}-x^{2}-3x-1=0$ I understand using a calculator to find the zeros is fairly easy, but I would like to learn how to solve this equation by hand. Thank you
5
votes
1answer
546 views

Distribute transpose on matrix multiplication

I need to do the following: Transpose[A.(B+C)]=Transpose[B].Transpose[A]+Transpose[C].Transpose[A] How should I do this in mathematica? So far mathematica does ...
1
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0answers
73 views

Sum of zeros in finite Galois field

In the following code: << FiniteFields` GF[2][{0}] + GF[2][{0}] == GF[2][{0}] GF[2][{0}] + GF[2][{0}] + GF[2][{0}] == GF[2][{0}] Why does the second line ...
1
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0answers
58 views

How to test for a non--zero rational function? [duplicate]

I want to test if a rational function in one variable is identically zero. I was surprised that just writing f==0 doesn't do it. I wrote the following code: <...
3
votes
4answers
913 views

How to Find “n” for n-th Triangular Number

For example, the 7th triangular number is 28. How do I create something that will tell me that 28 is the 7th triangular number? This is what I have created. ...
2
votes
1answer
95 views

Algebraic Manipulations with Indices

I am absolutely new to Mathematica, but I've heard it is a pretty powerful tool for symbolic calculations. My problem (stated generally): I have three dimensional array. I define a symbolic operator ...
4
votes
2answers
437 views

Using LeviCivitaTensor

I have 2 questions about using LeviCivitaTensor, based on the following session: The signs for the cross product seems to come out "opposite" of what I expected. Why is that? Did I miss anything? I ...
-1
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1answer
46 views

Different output, simple question [closed]

I found a slightly different output than what was expected in a book. DefSumMod[10] G={0,1,2,3,4,5,6,7,8,9} CircleGraph[G,Add[1]] Why is the tracing directed ...
1
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1answer
165 views

Factor bivariate polynomial over the complex numbers

This is very much like Factoring polynomials to factors involving complex coefficients except that I'm concerned about bivariate polynomials, not univariate polynomials. Take for example the ...
2
votes
1answer
221 views

Computing Poincaré symbolic solution for an arbitrary integer order polynomial

In the 1880s, Poincaré created functions which give the solution to the nth order polynomial equation in finite form. These functions turned out to be "natural" generalizations of the elliptic ...
0
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1answer
61 views

How to prevent factorial from being evalauted?

Suppose I have: Do[Print[i/i!], {i, 1, 10}] I would like the output to be like: 1/1!, 2/2!, 3/3! , ...,10/10! However, when I use the code above the ...
-1
votes
1answer
54 views

Computing $V(p_1, p_2)$ and determining whether $V(p_1) \subset V(p_2)$

Say I have two homogeneous polynomials $p_1, p_2 \in \mathbb{C}[x_0, \dots, x_n]$. In other words, they cut out co-dimension 1 varieties in $\mathbb{P}^n$. I would like to know how to compute two ...
2
votes
0answers
211 views

What are the steps using boolean algebra for transforming one equation into another?

I have a special case where I have two equations, which I have solved in a better and quicker way, but I need to solve with Boolean algebra. Using the laws of Boolean algebra, I have to prove that ...
0
votes
1answer
38 views

Variable as Difference of 2 Variables

I would like to evaluate a function based on the absolute difference of two variables. An example: g=5*x-5*x*y-5*y diff=x-y D[g,x] D[g,y] D[g,diff] I cannot find ...
7
votes
3answers
228 views

Ovals of plane curves (and esoteric surfaces in space)

Consider the curve $y^2 - x^3 + x=0$ with $x, y$ real. This curve has two connected components (one bounded, one not), and the question is: how do you get Mathematica to tell you that (if you do: <...
6
votes
1answer
385 views

Very serious multiplication bug when subscripts are used

I have found a serious bug in Mathematica 10.0.1.0 on mac os x. See the attached screenshot. It is applying the square root to the Mpc. I am very shocked by this. Does anyone know how to avoid this ...
1
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0answers
87 views

RSolve with simple initial condition

Suppose we have the following equation: $$ g_ma_m=r_ma_{m-1} $$ with initial condition $a_L=d$ and $L$ might be negative. The following command ...
0
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1answer
232 views

PolynomialReduce inconsistent results

I was playing around with gröbner basis and s-polynomials and I fell upon the PolynomialReduce, and I was wondering why it gives different results when I move around the polynomials in its second ...
1
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2answers
94 views

Solve gives a solution which is contradicted by an example

I have the problem as described in the title. Here is the code: ...
0
votes
1answer
194 views

Abstract algebra: define constants in a finite field

How can I to define a constant in $Z_{2}$? For example, I want to create a constant b that inherits the properties of an element from $Z_{2}$. For example ...
4
votes
1answer
212 views

Constructible numbers

Can Mathematica detect constructible numbers? I know it has MinimalPolynomial but for degrees higher than 4 it's not obvious whether a given polynomial yields a ...
4
votes
1answer
120 views

How does GroupActionBase affect the order of elements in a group?

Related (math.SE): How does the base of a group determine the “sort” of the elements in the group The help page for GroupActionBase says: A base of a group ...
6
votes
1answer
1k views

Polynomial GCD over a ring (with composite characteristic)

I'd like to implement the "Franklin-Reiter Related Message Attack" (see section 4.3 of Boneh's paper). As part of the implementation, I require to compute the GCD of two polynomials over $\mathbb{Z}_N[...
1
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1answer
136 views

Commutative algebra by generators and quadratic relations

My apologies if this has been asked before. Please also be gentle, as this is my first question here. I am trying to define a commutative algebra by generators and relations in the following way. ...
1
vote
1answer
1k views

Taking the LCM of algebraic expressions

Is it possible in Mathematica to take the LCM of an algebraic expression? For example, I want to take the LCM of $9$, $9y$, $12y^...
6
votes
1answer
1k views

Define operator algebra

My objective is to work out commutators like this $$[f(x,y)\partial_x^2+g(x,y)\partial_x+h(x,y),a(x,y)\partial_x^2+b(x,y)\partial_x+c(x,y)]$$ or $$[f(x,y)\partial_x^2+g(x,y)\partial_x+h(x,y),a(x,y)\...
5
votes
1answer
990 views

Simplifying polynomials in non-commutative variables

I would like to be able to simplify a polynomial in two non commuting variables, the desired result being that in every term one variable occurs to the left of the other variable. An example would be ...
4
votes
1answer
4k views

How to define custom operators

I am currently running Mathematica 8 and I would like to know how to define custom operators. Let's say I define an operator called $\times$ where: $$a\times b = a+a\cdot b+b$$ I also want to know ...
1
vote
0answers
45 views

How can I convert a list to an expression? [duplicate]

For example, I have the following list: {x1,op1,x2,op2,x3,op3,...} And I would like to convert the list to the following expression: x1 op1 x2 op2 x3 op3 ...
5
votes
2answers
3k views

Inverse of a polynomial in a polynomial ring

Let $N$ be a prime, and $q$ be a positive integer. Given a polynomial $f(x)$ in $R = \mathbb Z[x]/(x^N-1)$, I want to find another polynomial $f_q(x)$ in $R_q = \mathbb Z_q[x]/(x^N-1)$, such that $$f(...
10
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2answers
239 views

Unexpected behaviour of SeriesCoefficient?

Following this question/answer I discovered and played with SeriesCoefficient. In particular, I tried ...