| 12/2001 |
A ``REGRA DOS 70'', O TEMPO DE DUPLICA\c{C}\~{A}O E A MEIA-VIDA Antônio Carlos Gilli Martins  rp-2001-12.pdf |
| 11/2001 |
Existence and uniqueness of strong solutions of flows of asymmetric fluids in unbounded domain José Luiz Boldrini, Marko A. Rojas-Medar, M. Durán We consider and initial boundary value problem for a system of equations describing nonstationary flows of incompressible asymmetric fluids in unbounded domains. Under conditions similar to the ones for the usual Navier-Stokes equations, we prove the existence and uniqueness of strong solutions. rp-2001-11.pdf |
| 10/2001 |
Strong periodic solutions for a class of abstract evolution equations G. Lukaszewicz, E. E. Ortega-Torres, Marko A. Rojas-Medar We consider a class of abstract evolution equations in a Hilbert space for which we prove existence and uniqueness of strong time periodic solutions. The result covers many models in hydrodynamics. rp-2001-10.pdf |
| 9/2001 |
Variedades de conexão para fluxos Morse-Smale Maria Alice Bertolim rp-2001-9.pdf |
| 8/2001 |
Invariant almost Hermitian structures on flag manifolds Luiz A. B. San Martin, Caio J. C. Negreiros Let $G$ be a complex semi-simple Lie group and form its maximal flag manifold $\Bbb{F}=G/P=U/T$ where $P$ is a minimal parabolic subgroup, $U$ a compact real form and $T=U\cap P$ a maximal torus of $U$. We study $U$ -invariant almost Hermitian structures on $\Bbb{F}$. The $\left( 1,2\right) $ -symplectic (or quasi-K\"{a}hler) structures are naturally related to the affine Weyl groups. A special form for them, involving abelian ideals of a Borel subalgebra, is derived. From the $\left( 1,2\right)$-symplectic structures a classification of the whole set of invariant structures is provided, showing, in particular, that near K\"{a}hler invariant structures are K\"{a}hler, except in the $A_{2}$ case. rp-2001-8.pdf |
| 7/2001 |
Vector fields on manifolds with boundary, discontinuities and reversibility Marco A. Teixeira rp-2001-7.pdf |
| 6/2001 |
Existence of weak solutions of micropolar fluid equations in a time dependent domain Ana Jaime Resendiz B., Marko A. Rojas-Medar In this paper we study the existence of weak solutions of the initial-boundary value problem for micropolar equations in domains with smoothly moving boundaries. rp-2001-6.pdf |
| 5/2001 |
A review of non-parametric curve estimation methods with application to Econometrics Ronaldo Dias Various features of econometric data can be analyzed by non-parametric approach. This review summarizes some of the most important procedures in curve estimation that has been very useful in the field of econometrics. Specifically, it describes the theory and the applications of non-parametric density and regression estimation problems with emphases in kernel, nearest neighbor, variable kernel, orthogonal series, smoothing splines, logsplines and H-splines methods. rp-2001-5.pdf |
| 4/2001 |
A basis for the graded identities of the matrix algebra of order two over a finite field of characteristic $p\neq 2$ Plamen Koshlukov, Sérgio S. de Azevedo Let $K$ be a finite field of characteristic $p>2$, and let $M_2(K)$ be the matrix algebra of order two over $K$. We describe up to a graded isomorphism the 2-gradings of $M_2(K)$. It turns out there are only two nonisomorphic nontrivial such gradings. Furthermore we exhibit bases of the graded polynomial identities for each one of these two gradings. One can distinguish these two gradings by means of the graded polynomial identities they satisfy. rp-2001-4.pdf |
| 3/2001 |
Sub-Riemannian Geodesics on Lie Groups Odinette Renée Abib We investigate the space of abnormal extremals of nonlinear deterministic control systems which are linear in the controls. Our main results concern the abnormal curves for a class of systems whose state spaces are nilpotent Lie groups. rp-2001-3.pdf |
