6 papers
Are scales Fréchet?
Raul Figueroa-Sierra, Osvaldo Guzmán, Michael Hrušák +1
We continue the study of Dow spaces of a -scale, originally introduced by Alan Dow in "-Weight and the Fréchet-Urysohn property" (Topology and its Applications, Vo…
Properties of Laver forcing associated with a co-ideal expressed via the Katetov order
Osvaldo Guzmán, Francisco Santiago Nieto-de la Rosa, Ulises Ariet Ramos-Garcia
We study variants of classical Laver forcing defined from co-ideals and analyze their combinatorial properties in terms of the Katětov order. In particular, we give a Katětov-theor…
Shelah Ultrafilters
Emmanuel Balderas, David Chodounský, Osvaldo Guzmán
In this paper, we study a special type of ultrafilter which we call Shelah ultrafilter. We show that it is possible to add a Shelah ultrafilter using a special forcing notion. We a…
Diamonds on trees
Osvaldo Guzmán, Carlos López-Callejas
We generalize the diamond principle and its variants using the notion of stationarity in trees introduced by Brodsky in [Brodsky, A. M., A theory of stationary trees and the balanc…
Construction schemes: transferring structures from to
Jorge Antonio Cruz Chapital, Osvaldo Guzmán, Stevo Todorcevic
A structural analysis of construction schemes is developed. That analysis is used to give simple and new constructions of combinatorial objects which have been of interest to set t…
High dimensional sequential compactness
César Corral, Osvaldo Guzmán, Carlos López-Callejas
We give examples of -sequentially compact spaces that are not -sequentially compact under several assumptions. We improve results from Kubis and Szeptycki by building suc…