| 27/2004 |
Completeness Conditions in Certain Weyl Complexes, Combinatorics and Parsimony Mari Sano We describe the combinatorial relationship between different completeness theorems in the Buchsbaum-Rota resolutionof Weyl modules. In particular this gives a completely elementary, combinatorial description of the Buchsbaum-Rota construction that shows that it is a resolution.  rp-2004-27.pdf |
| 26/2004 |
Fórmula Explícita e Interpretação Combinatória para os Números de Fibonacci I. M. Craveiro, José Plínio O. Santos rp-2004-26.pdf |
| 25/2004 |
Prova Alternativa para a Identidade 12 de Slater I. M. Craveiro, José Plínio O. Santos rp-2004-25.pdf |
| 24/2004 |
A Sequential Quadratic Programming Algorithm with a Piecewise Linear Merit Function Francisco A. M. Gomes Neto A sequential quadratic programming algorithm for solving nonlinear programming problems is presented. The new feature of the algorithm is related to the definition of the merit function. Instead of using one penalty parameter per iteration and increasing it as the algorithm progresses, we suggest that a new point is to be accepted if it stays sufficiently below the piecewise linear function defined by some previous iterates on the $(f; ||C||^2_2)$ space. Therefore, the penalty parameter is allowed to decrease between successive iterations. Besides, one need not to decide how to update the penalty parameter. This approach resembles the filter method introduced by Fletcher and Leyffer [7], but it is less tolerant since a merit function is still used. rp-2004-24.pdf |
| 23/2004 |
Multiple Solutions for an Elliptic Equation with Critical Hardy-Sobolev Exponents Via the Domain Topology Marcelo F. Furtado Let $\Omega \subset \real^N$ be a smooth bounded domain such that $0 \in \Omega$, $N \geq 3$, $0 \leq s rp-2004-23.pdf |
| 22/2004 |
Reproductivity for a Nematic Liquid Crystal Model Blanca Climent-Ezquerra, Francisco Guillén-Gonzáles, Marko A. Rojas-Medar In this paper we prove existence of weak solution with the reproductivity in time property, for a penalized PDE's system related to a nematic liquid crystal model. This problem is relatively explicit when timeindependent Dirichlet boundary conditions are imposed for the orientation of crystal molecules. For the timedependent case, the verification of a maximum principle for weak reproductive solutions is fundamental in the argument. Finally, the relation between reproductive and periodic in time solutions and their dependence respect to the regularity will be pointed out, being completely different the 2D and 3D cases. rp-2004-22.pdf |
| 21/2004 |
Continuity for S-Convex Fuzzy Processes Juliana Cervelati, María Dolores Jiménez-Gamero, Filidor E. Vilca-Labra, Marko A. Rojas-Medar In a previous paper we introduced the concept of s-convex fuzzy mapping and established some properties. In this work we study the continuity for s-convex fuzzy processes. rp-2004-21.pdf |
| 20/2004 |
Analysis of Variance for Genomic Sequences in Unbalanced Designs Roberta de Souza, Hildete P. Pinheiro, Cibele Q. da Silva, Sérgio F. dos Reis In the study of genetic divergence among organisms, generally the analysis is done directly from the DNA molecule. Therefore, a possible outcome is categorical being one out of four categories (looking at the nucleotide level). Light \& Margolin (1971) developed an analysis of variance for categorical data (CATANOVA) and Pinheiro et al. (2000) employed a similar measure of variation and extended the CATANOVA procedure taking into account several positions in the sequence for balanced designs. Here we consider variable number of sequences in each group, that is, the samples are unbalanced. In order to test the null hypothesis of homogeneity among groups, the asymptotic distribution of the test statistic was found and its power is evaluated. An application of the test to real data is illustrated using resampling methods such as the bootstrap to generate the empirical distribution of the test statistics. rp-2004-20.pdf |
| 19/2004 |
Homotopies for the Generalized Bar Complex Associated to Certain 3-Rowed Weyl Modules Mari Sano In \cite{BR2}, Buchsbaum and Rota presented a generalized bar complex associated to certain 3-rowed Weyl modules and proved that this complex is in fact a resolution via an induction on the number of overlaps between the second and third rows and a fundamental exact sequence (\cite{AB}). In this paper we study the structure of this resolution by constructing a splitting contracting homotopy for the complexes corresponding to certain shapes. We also use the method of proof to give a basis for the syzygies that is more structured than the basis given in \cite{sano}. rp-2004-19.pdf |
| 18/2004 |
Estudo do Desempenho de Métodos para Minimização Irrestrita com Controle de Passo Sandra A. Santos, Larissa Oliveira Xavier rp-2004-18.pdf |
