Volume 02 (1998) No. 2
Volume 02 (1998) No. 2 
On the role of groups in topology and geometry
R. James Milgram
Abstract:
In this article we develop some relationships between fundamental concepts in geometry and topology and structures in (mostly) the theory of finite groups. In particular, we stress the way in which classical results in group theory relate to topology and have given rise to new developments in homotopy theory. We describe work in progress motivated by these relationships both in low dimensional topology and in homotopy theory.
Foliated bundles and metric rigidity
Raúl Quiroga Barranco
Abstract:
We obtain a Hermitian metric rigidity theorem for foliated vector bundles other than the leafwise tangent bundle, allowing us to develop results not considered in [29]. In particular, we obtain as a consequence a vanishing theorem for the leafwise cohomology of a foliation, which has as a corollary a partial vanishing result of certain holomorphic 1-forms on suitable compact Kaehler manifolds, and a rigidity property for holomorphic equivalences of foliations by irreducible bounded symmetric domains with complex dimension $\ge 2$.
El teorema de Van Kampen y aplicaciones
Eduardo González y Jesús González
Abstract:
En este artículo revisamos una generalización del teorema clásico de Van Kampen y, mediante el uso de la teoría de espacios recubridores, analizamos aplicaciones a la teoría de grupos libres no abelianos.
Adoquinado de cuadrados con trominós rectos y de cubos con tricubos rectos
Francisco J. Zaragoza Martínez
Abstract:
Sea $n$ un entero positivo. En este artículo se prueba que para todo cuadrado de lado $n$ ($n \ne 3$ y $5$) existe un adoquinado libre de fallas con trominós rectos. También se prueba que todo cubo de lado $n$ se puede adoquinar con tricubos rectos. Estos resultados extienden los obtenidos por Golomb en 1954 y por Chu y Johnsonbaugh en 1986.
Cancellation laws in topological products
Eduardo Santillán Zerón
Abstract:
Given three spaces $A$, $B$ and $H$ such that $A \times H$ is homeomorphic to $B \times H$, when are $A$ and $B$ homeomorphic? In this paper we answer positively this old question when $A$ and $B$ are subsets of the real line and $H$ is connected.
An example of a bounded-in-probability, but non-tight Markov chain
Juan González Hernández y Rubén Pérez Hernández
Abstract:
This paper shows an example of a non-tight Markov chain which is bounded in probability.