El laboratorio de Matemáticas : un reto pendiente.

El proyecto se realiza en la Escuela Politécnica Superior de Burgos (E.P.S), lugar donde trabajan los 16 profesores del Grupo de Didáctica de las Matemáticas en las Escuelas Técnicas de la UBU. Los objetivos son: motivación del profesorado para que dedique una parte importante de su labor a la mejora de la calidad de su tarea docente, utilización de las nuevas tecnologías, contextualización de las Matemáticas en las asignaturas de Ingeniería, puesta en marcha del laboratorio de Matemáticas en las 7 titulaciones de la (E.P.S.), potenciación y actualización de los recursos informáticos, intercambio de experiencias y campos de aplicación con otros grupos de profesores, áreas de conocimiento, niveles de enseñanza, etc. El sistema de trabajo llevado a cabo consiste en reuniones de los profesores que integran el proyecto, contactos con los profesores de las asignaturas de Ingeniería, asistencia a congresos, elaboración y revisión constante de las prácticas de laboratorio. Para el desarrollo del proyecto comenzamos desarrollando prácticas con el programa Derive en el ámbito de las asignaturas troncales de los primeros cursos. Para las asignaturas de Estadística las prácticas se han desarrollado con statgraphics y se han consolidado en 5 asignaturas. En las asignaturas con contenidos de Análisis Numérico hemos introducido Matlab para el numérico y Derive y Maple para el simbólico. Los ámbitos en que ha incidido la experiencia, son además de en E.P.S. de Burgos, en las comunicaciones del VI Congreso Regional Castellano-Leonés de Educación Matemática (2000), Las X Jornadas para el Aprendizaje y la Enseñanza de las Matemáticas (J A E M - 1001), y en los Cursos de Especialización para profesores de Enseñanzas Medias (2001). Dentro de los resultados obtenidos hemos observado una disminución del fracaso escolar, se ha puesto en marcha del laboratorio, enunciado de problemas y las prácticas de laboratorio, generación de software para el aprendizaje. Los materiales utilizados, son principalmente Software: DERIVE, STATGRAPHICS, MATLAB Y MATHEMATICA. No se han publicado los resultados. Sí aparecen publicadas las 12 comunicaciones a congresos en las actas correspondientes.

Evaluación previa y nuevas tecnologías en la enseñanza de la estática.

Se han realizado dos tipos de trabajo. El primero ha consistido en la recogida de información por parte de un profesor que asistía a la clase de los demás. Con ese material se han realizado lista de conocimientos previos que los alumnos han de tener para abordar la asignatura. Se ha diseñado una herramienta para que los alumnos midan el grado de cumplimiento de esos conocimientos previos. Además se han elaborado los objetivos específicos para la asignatura objeto del proyecto: Mecánica Aplicada. En una etapa posterior los test se han administrado a los alumnos. El segundo tipo de trabajo ha consistido en la elaboración de guiones didácticos para la realización de prácticas de laboratorio. Las prácticas, tanto de tipo computacional como empírico y mixto se realizan con el apoyo de un lenguaje para cálculo simbólico (Mathematica). Estas son: 1)Ensayo de flexión. Análisis computacional; 2) Cálculo computacional de una estructura articulada isostática; 3) Cálculo de un problema de sistemas de vectores deslizantes; 4) Cálculo computacional de los valores estáticos de una superficie plana; 5) Estudio experimental de la fuerza de rozamiento; 6) Descomposición de fuerzas.

Statistical isomorphism of three-level factional factorial designs

From a statistician's standpoint, the interesting kind of isomorphism for fractional factorial designs depends on the statistical application. Combinatorially isomorphic fractional factorial designs may have different statistical properties when factors are quantitative. This idea is illustrated by using Latin squares of order 3 to obtain fractions of the 3(3) factorial. design in 18 runs.

A geometric approach to generalized Stokes conjectures

We consider the Stokes conjecture concerning the shape of extreme two-dimensional water waves. By new geometric methods including a nonlinear frequency formula, we prove the Stokes conjecture in the original variables. Our results do not rely on structural assumptions needed in previous results such as isolated singularities, symmetry and monotonicity. Part of our results extends to the mathematical problem in higher dimensions.

The physical pendulum in an advanced undergraduate course in mechanics

The physical pendulum treated with a Hamiltonian formulation is a natural topic for study in a course in advanced classical mechanics. For the past three years, we have been offering a series of problem sets studying this system numerically in our third-year undergraduate courses in mechanics. The problem sets investigate the physics of the pendulum in ways not easily accessible without computer technology and explore various algorithms for solving mechanics problems. Our computational physics is based on Mathematica with some C communicating with Mathematica, although nothing in this paper is dependent on that choice. We have nonetheless found this system, and particularly its graphics, to be a good one for use with undergraduates.

On universal and periodic β-expansions, and the Hausdorff dimension of the set of all expansions

We study the topology of a set naturally arising from the study of β-expansions. After proving several elementary results for this set we study the case when our base is Pisot. In this case we give necessary and sufficient conditions for this set to be finite. This finiteness property will allow us to generalise a theorem due to Schmidt and will provide the motivation for sufficient conditions under which the growth rate and Hausdorff dimension of the set of β-expansions are equal and explicitly calculable.

The curve selection lemma and the Morse-Sard theorem

We use an inequality due to Bochnak and Lojasiewicz, which follows from the Curve Selection Lemma of real algebraic geometry in order to prove that, given a C(r) function f : U subset of R(m) -> R, we have lim(y -> xy is an element of crit(f)) vertical bar f(y) - f(x)vertical bar/vertical bar y - x vertical bar(r) = 0, for all x is an element of crit(f)` boolean AND U, where crit( f) = {x is an element of U vertical bar df ( x) = 0}. This shows that the so-called Morse decomposition of the critical set, used in the classical proof of the Morse-Sard theorem, is not necessary: the conclusion of the Morse decomposition lemma holds for the whole critical set. We use this result to give a simple proof of the classical Morse-Sard theorem ( with sharp differentiability assumptions).

Finite determinacy and Whitney equisingularity of map germs from C(n) to C(2n-1)

We show that a holomorphic map germ f : (C(n), 0) -> (C(2n-1), 0) is finitely determined if and only if the double point scheme D(f) is a reduced curve. If n >= 3, we have that mu(D(2)(f)) = 2 mu(D(2)(f)/S(2))+C(f)-1, where D(2)(f) is the lifting of the double point curve in (C(n) x C(n), 0), mu(X) denotes the Milnor number of X and C(f) is the number of cross-caps that appear in a stable deformation of f. Moreover, we consider an unfolding F(t, x) = (t, f(t)(x)) of f and show that if F is mu-constant, then it is excellent in the sense of Gaffney. Finally, we find a minimal set of invariants whose constancy in the family f(t) is equivalent to the Whitney equisingularity of F. We also give an example of an unfolding which is topologically trivial, but it is not Whitney equisingular.

Improved likelihood inference for the shape parameter in Weibull regression

We obtain adjustments to the profile likelihood function in Weibull regression models with and without censoring. Specifically, we consider two different modified profile likelihoods: (i) the one proposed by Cox and Reid [Cox, D.R. and Reid, N., 1987, Parameter orthogonality and approximate conditional inference. Journal of the Royal Statistical Society B, 49, 1-39.], and (ii) an approximation to the one proposed by Barndorff-Nielsen [Barndorff-Nielsen, O.E., 1983, On a formula for the distribution of the maximum likelihood estimator. Biometrika, 70, 343-365.], the approximation having been obtained using the results by Fraser and Reid [Fraser, D.A.S. and Reid, N., 1995, Ancillaries and third-order significance. Utilitas Mathematica, 47, 33-53.] and by Fraser et al. [Fraser, D.A.S., Reid, N. and Wu, J., 1999, A simple formula for tail probabilities for frequentist and Bayesian inference. Biometrika, 86, 655-661.]. We focus on point estimation and likelihood ratio tests on the shape parameter in the class of Weibull regression models. We derive some distributional properties of the different maximum likelihood estimators and likelihood ratio tests. The numerical evidence presented in the paper favors the approximation to Barndorff-Nielsen`s adjustment.

On automorphisms of split metacyclic groups

Let D( m, n; k) be the semi-direct product of two finite cyclic groups Z/m = < x > and Z/n = < y >, where the action is given by yxy(-1) = x(k). In particular, this includes the dihedral groups D(2m). We calculate the automorphism group Aut (D(m, n; k)).

THE FUNDAMENTAL GROUP OF THE SPACE OF MAPS FROM A SURFACE INTO THE PROJECTIVE PLANE

In this work we compute the fundamental group of each connected component of the function space of maps from it closed surface into the projective space

Extensions of homogeneous polynomials ON c(0)(l(2)(i))

We show that a 2-homogeneous polynomial on the complex Banach space c(0)(l(2)(i)) is norm attaining if and only if it is finite (i.e, depends only on finite coordinates). As the consequence, we show that there exists a unique norm-preserving extension for norm-attaining 2-homogeneous polynomials on c(0)(l(2)(i)).

On automorphisms of finite abelian p-groups

Let A be a finitely generated abelian group. We describe the automorphism group Aut(A) using the rank of A and its torsion part p-part A(p). For a finite abelian p-group A of type (k(1),..., k(n)), simple necessary and sufficient conditions for an n x n-matrix over integers to be associated with an automorphism of A are presented. Then, the automorphism group Aut(A) for a finite p-group A of type (k(1), k(2)) is analyzed. (C) 2008 Mathematical Institute Slovak Academy of Sciences.