All Questions
Tagged with groebner-bases ag.algebraic-geometry
37 questions
1
vote
0
answers
41
views
Example polynomial system where Macaulay bound is tight
I have been solving systems of polynomial equations by forming the Macaulay matrix of different degrees and computing its null space. If the degree is large enough, namely at or above the degree of ...
- 11
1
vote
0
answers
85
views
Are there algorithms for lowering the degree of the polynomials which generate an ideal by strategically adding new variables?
Suppose I have an ideal $I$ in a polynomial ring $F[x_1,...,x_n]$ generated by a few polynomials of maximum degree $k$.
I want to embed the ideal $I$ into a larger ideal $J$ in a larger ring with ...
- 11
0
votes
0
answers
52
views
Solving sparse bilinear systems with a relatively large number of variables
I'm trying to solve a bilinear system of equations over a finite field. (More specifically: I'm trying to find a single solution, if one exists.) The system consists of equations of the form
$$y^T A_i ...
- 101
2
votes
0
answers
88
views
Gröbner implicitization with relationships between the variables
I have the following parametric equations, where cost$=\cos t$, cos2t$=\cos 2t$, and $A^2+B^2=1$:
...
- 2,560
3
votes
1
answer
271
views
Resultants and elimination theory
Consider an ideal $I = \langle f_1,\dotsc,f_n\rangle$ in the ring $k[x_1,\dotsc,x_m]$.
Define the $i$-th elimination ideal to be $I_i = I \cap k[x_{i+1},\dotsc,x_m]$.
For any two polynomials $f$ and $...
- 1,435
0
votes
1
answer
190
views
Compatibility conditions for quadratic equations
In the context of physics, I stumbled over the following problem: I have $N$ equations, all are quadratic in a single scalar, real variable $x$:
\begin{eqnarray}
0 &= A_1x^2 + B_1x + C_1 \\
&...
3
votes
1
answer
355
views
Groebner basis with parameters
I need to compute a Groebner basis of a polynomial system with parameters.
The only recent results I found is Groebner cover:
https://www.sciencedirect.com/science/article/pii/S0747717110000970
Are ...
- 65
2
votes
1
answer
155
views
Library/Database of parametric polynomial systems
Could anyone please recommend a known website where I can find a database/library that has systems of polynomial equations with $n$ variables and $m$ parameters?
I need some real examples to test my ...
4
votes
0
answers
122
views
Recommendations for distributed calculations of Groebner Bases
There are many computer algebra systems available which can compute a Groebner basis, including:
Mathematica
Singular
Macaulay2
Magma
Maple
CoCoA
However (please correct me if I've missed something) ...
- 61
2
votes
1
answer
189
views
Techniques for estimating dimension of algebraic variety without calculating Groebner basis of polynomial constraints?
I have a system of multilinear polynomial constraints that I believe has no solution. Unfortunately, the number of variables and number of constraints is too large to afford direct computation of a ...
- 61
1
vote
1
answer
174
views
Sufficient syntactic conditions for zero-dimensionality of polynomial systems
Consider a system $S$ of polynomial equations, $p_1=0,...,p_m=0$, for $p_i\in K[x_1,...,x_n]$, for a field $K$: the system $S$ is zero-dimensional if it has finitely many solutions. It is well-known ...
- 333
0
votes
0
answers
55
views
Dependence of the complexity of solving polynomial sytems on the multidegree
Let $f_1,\ldots,f_n\in \mathbb{Q}[X_1,\ldots,X_n]$ be a system of $n$ polynomials in $n$ indeterminant, which only has finitely many solutions. Supose that the each of the variables $X_i$ appears at ...
- 1
10
votes
0
answers
573
views
How general are Gröbner degenerations?
While working with flat degenerations of flag varieties and Schubert varieties I've noticed that among the numerous known constructions there doesn't seem to be a single one that doesn't turn out to ...
- 3,513
2
votes
0
answers
71
views
grobner basis of an ideal dependent on some parameter
Suppose $I = \langle f_1, ... , f_l \rangle$ is an ideal generated by polynomials $f \in k[x_1,\dots,x_n]$, where $k$ is a field of rational functions in some parameters $s_1,\dots,s_m$.
What are the ...
- 1,435
1
vote
0
answers
130
views
Groebner basis of a toric ideal
I know about toric ideals that it is a sort of binomial ideal i.e. generated by $x^u - x^v$, where $Au = Av $ ( A is the associated matrix). So by finding all integer solutions of $AX = 0$, can we ...
8
votes
1
answer
656
views
Given a zero-dimensional ideal $(f_1,...,f_n)$, is the ideal $(f_1-\alpha_1,...,f_n-\alpha_n)$ also zero-dimensional?
Suppose you have a zero-dimensional ideal $I=(f_1,...,f_n)$ in a polynomial ring $R=k[x_1,...,x_n]$ over a field $k$, so that $\dim_k(R/I)<\infty$. Take indeterminates $\alpha_1,...,\alpha_n$ and ...
- 573
2
votes
0
answers
237
views
Computing the codimension of the variety defined by a system of quadratic forms
Suppose I have an $m \times n$ matrix $L$, where $m \leq n$ and each entry is $L_{i,j}(x_1, ..., x_s)$ which is a linear form over $\mathbb{C}$. Let $\mathbf{y} = (y_1, \ldots, y_n)$. Let us consider ...
- 3,625
5
votes
2
answers
983
views
Automatic proof in Euclidean Geometry using Theory of Groebner Bases
I've done the same question in math.stackexchange here "https://math.stackexchange.com/questions/1938261/automatic-proof-in-euclidean-geometry-using-theory-of-groebner-bases?noredirect=1#...
- 441
2
votes
1
answer
529
views
Integer programming and Groebner basis
I enjoyed reading different papers about using Groebner basis to solve integer programming.
Is there any literature about the complexity and/or comparison with other (more classical) methods like ...
- 337
2
votes
2
answers
3k
views
Solving a system of equations using Gröbner basis
In Sage (or any other package) when using Gröbner basis to solve a system of equations (some of which are non-linear equations) does computing the Gröbner basis for the ideal ID generated by the ...
- 23
4
votes
1
answer
547
views
How can I include irreducibility in a Groebner basis calculation?
I'm trying to prove impossibility of certain systems of differential/polynomial equations using Groebner basis techniques.
For example, consider the equation $qn = mf$, where each of the variables ...
- 415
4
votes
1
answer
244
views
Solving over-determined system of polynomials
I am trying to solve the following over determined system of polynomials
\begin{align}
& p_1(x_1,x_2,\ldots,x_n)=0, \\
& p_2(x_1,x_2,\ldots,x_n)=0, \\
& \vdots \\
& p_m(x_1,x_2, \...
- 141
16
votes
2
answers
721
views
From polynomial ideal over $\mathbb{Q}$ to polynomial ideal over $\mathbb{Z}$
Is there an algorithm to compute, given a polynomial ideal $I\subset \mathbb{Q}[x_1,\dotsc,x_n]$, the ideal $I\cap \mathbb{Z}[x_1,\dotsc,x_n]$ in $\mathbb{Z}[x_1,\dotsc,x_n]$?
The input and output ...
- 7,826
1
vote
2
answers
191
views
Pseudo-decision procedures for first order arithmetic
I was reading this paper http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.117.2911&rep=rep1&type=pdf in which the author describes an algorithm, based on Groebner basis, ...
- 19
1
vote
1
answer
470
views
cup-length of the first Chern class of complex grassmannian
Let $G_2(\mathbb{C}^{n+1})$ be the complex grassmannian.
Then the cohomology ring $H^*(G_2(\mathbb{C}^{n+1});\mathbb{C})=\mathbb{C}[c_1,c_2]/(f_n,f_{n+1})$, where $f_k=\sum_{i=0}^{[k/2]}(-1)^{k-i}{{...
- 1,990
2
votes
3
answers
2k
views
ideals of polynomial ring with complex number coefficients
Let $\mathbb{C}[x,y]$ be the polynomial ring with variables $x,y$ and coefficient in $\mathbb{C}$.
Let $f,g\in \mathbb{C}[x,y]$.
Let $(f,g)$ be the ideal of $\mathbb{C}[x,y]$ generated by $f,g$.
...
- 1,990
1
vote
1
answer
558
views
Is there a Gröbner basis analogue that exists for vector spaces?
Suppose I have a coordinate system $t_1,\ldots t_N$ with a lexicographical ordering. Let LT denote choosing the lowest term of a polynomial with respect to this ordering. e.g. LT$(t_1 + t_2)=t_2$.
...
- 131
12
votes
1
answer
2k
views
Ways to show a system of polynomial equations has no solution
I came across the following system of polynomial equations on $X_1,\dots,X_{m-2}$:
$$
\begin{cases}
2X_{2s}+\sum\limits_{t=1}^{2s-1}(-1)^tX_tX_{2s-t}=0,\quad s=1,\dots,\frac{m}{2}-1,\\
X_sX_{m-s}+(-1)^...
- 767
4
votes
0
answers
168
views
Bound for the height of equations defining the singular locus of a variety
Fix positive integers $m, n, d$.
In what follows, the height of an algebraic number will mean the absolute multiplicative height.
Let $V \subset \bar{\mathbb{Q}}^n$ be an affine algebraic variety ...
- 1,500
0
votes
2
answers
416
views
Computing toric ideals via saturation and Groebner bases of toric ideals
About a month ago I asked this question on math.stackexchange and unfortunately there was no response. Perhaps someone here knows the answer.
Let $A \in \mathbb{Z}^{m \times n}$ be a matrix of full ...
- 103
14
votes
1
answer
2k
views
Gröbner basis for Sudoku
I'm trying to write a program that solves Sudokus using Gröbner bases. I introduced $81$ variables, $x_1$ to $x_{81}$, this is a linearisation of the Sudoku board.
The space of valid Sudokus is ...
- 371
5
votes
1
answer
3k
views
Existence of a real-valued solution to system of multivariate polynomial equations
Given a system of multivariate, polynomial equations, is there a way to determine if it has a solution in a given field (for instance the set of all reals). I don't care what the solution is, I just ...
- 53
2
votes
2
answers
600
views
Nonstandard monomial orders?
Are there any articles/books/examples where a non-standard monomial order is used?
What are the applications of these monomial orders? In particular, uses in groebner bases and variable elimination.
(...
- 15.8k
4
votes
2
answers
3k
views
Numerical solution for a system of multivariate polynomial equations
Hi all,
I have a system of 6th-order polynomial equations in 4 variables $q_1, q_2, q_3, q_4$ (i.e. polynomials with all the terms such as $q_1^6, q_2^6, q_2^4 q_3^2$):
$P_k(q_1, q_2, q_3, q_4) = 0$ ...
- 113
4
votes
4
answers
444
views
Lower bounds on the degrees of representatives of $u^n$ as $n \to \infty$
Let $k$ be an algebraically closed field and $A$ a finitely generated $k$-algebra, together with a specified surjective morphism $\phi \colon k[x_1, \dotsc, x_n] \to A$. For $f \in A$, define $\...
- 7,328
1
vote
1
answer
375
views
Any implemented algorithm to compute the closure of an affine variety in a product of projective spaces?
Let $I$ be an ideal of $k[x_1, \ldots, x_m, y_1, \ldots, y_n]$, $k$ being a field. Does any of the computer algebra systems implement any algorithm to calculate the generators of the 'bi-...
- 5,339
28
votes
4
answers
3k
views
Can Gröbner bases be used to compute solutions to large, real-world problems?
In particular, suppose I have an affine algebraic variety over $\mathbb{R}^n$ described by generators of a radical ideal $I$ and I want to find (perhaps not all of the) points in the variety. Several ...
- 3,059