4 papers · 1 filter
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…