arXiv subjects
Publications and source records attributed to Antonio Montes.
We consider a counter-intuitive regime of stimulated Brillouin scattering in which the pump wave absorbs the phase defects of the Stokes wave, yielding a nonlinear self-stabilisation of the acoustic wave and a narrowing of the acoustic spectrum
The main idea in this paper is merging two techniques that have been recently developed. On the one hand, we consider MCCGS, standing for Minimal Canonical Comprehensive Groebner Systems, a recently introduced computational tool yielding "good" bases for ideals of polynomials over a field depending on several parameters, that specialize "well", for instance, regarding the number of solutions for the given ideal, for different values of the parameters. The second ingredient concerns automatic theorem discovery in elementary geometry. Automatic discovery aims to obtain complementary hypotheses for a (generally false) geometric statement to become true. The paper shows how to use MCCGS for automatic discovering of theorems and gives relevant examples.
Given a parametric polynomial ideal I, the algorithm DISPGB, introduced by the author in 2002, builds up a binary tree describing a dichotomic discussion of the different reduced Groebner bases depending on the values of the parameters, whose set of terminal vertices form a Comprehensive Groebner System (CGS). It is relevant to obtain CGS's having further properties in order to make them more useful for the applications. In this paper the interest is focused on obtaining a canonical CGS. We define the objective, show the difficulties and formulate a natural conjecture. If the conjecture is true then such a canonical CGS will exist and can be computed. We also give an algorithm to transform our original CGS in this direction and show its utility in applications.
This is the continuation of Montes' paper "On the canonical discussion of polynomial systems with parameters". In this paper we define the Minimal Canonical Comprehensive Groebner System (MCCGS) of a parametric ideal and fix under which hypothesis it exists and is computable. An algorithm to obtain a canonical description of the segments of the MCCGS is given, completing so the whole MCCGS algorithm (implemented in Maple). We show its high utility for applications, like automatic theorem proving and discovering, and compare it with other existing methods. A way to detect a counterexample is outlined, although the high number of tests done give evidence of the existence of the MCCGS.
Let $C(n,p)$ be the set of $p$-compositions of an integer $n$, i.e., the set of $p$-tuples $\bmα=(α_1,...,α_p)$ of nonnegative integers such that $α_1+...+α_p=n$, and $\mathbf{x}=(x_1,...,x_p)$ a vector of indeterminates. For $\bmα$ and ${\bmβ}$ two $p$-compositions of $n$, define $(\mathbf{x}+\bmα)^{\bmβ} = (x_1+α_1)^{β_1}... x_p+α_p)^{β_p}$. In this paper we prove an explicit formula for the determinant $\det_{\bmα,{\bmβ}\in C(n,p)}((\mathbf{x}+\bmα)^{\bmβ})$. In the case $x_1=...=x_p$ the formula gives a proof of a conjecture by C.~Krattenthaler.
Let $Φ(x,y)$ be a bivariate polynomial with complex coefficients. The zeroes of $Φ(x,y)$ are given a combinatorial structure by considering them as arcs of a directed graph $G(Φ)$. This paper studies some relationship between the polynomial $Φ(x,y)$ and the structure of $G(Φ)$.
In 1992, V. Weispfenning proved the existence of Comprehensive Groebner Bases (CGB) and gave an algorithm to compute one. That algorithm was not very efficient and not canonical. Using his suggestions, A. Montes obtained in 2002 a more efficient algorithm (DISPGB) for Discussing Parametric Groebner Bases. Inspired in its philosophy, V. Weispfenning defined, in 2002, how to obtain a Canonical Comprehensive Groebner Basis (CCGB) for parametric polynomial ideals, and provided a constructive method. In this paper we use Weispfenning's CCGB ideas to make substantial improvements on Montes DISPGB algorithm. It now includes rewriting of the discussion tree using the Discriminant Ideal and provides a compact and effective discussion. We also describe the new algorithms in the DPGB library containing the improved DISPGB as well as new routines to check whether a given basis is a CGB or not, and to obtain a CGB. Examples and tests are also provided.
Let $Φ(x,y)\in\mathbb{C}[x,y]$ be a symmetric polynomial of partial degree $d$. The graph $G(Φ)$ is defined by taking $\mathbb{C}$ as set of vertices and the points of $\mathbb{V}(Φ(x,y))$ as edges. We study the following problem: given a finite, connected, $d$-regular graph $H$, find the polynomials $Φ(x,y)$ such that $G(Φ)$ has some connected component isomorphic to $H$ and, in this case, if $G(Φ)$ has (almost) all components isomorphic to $H$. The problem is solved by associating to $H$ a characteristic ideal which offers a new perspective to the conjecture formulated in a previous paper, and allows to reduce its scope. In the second part, we determine the characteristic ideal for cycles of lengths $\le 5$ and for complete graphs of order $\le 6$. This results provide new evidence for the conjecture.