abstract
Symmetries between two Ramsey properties
Lorenz Halbeisen
In this article we compare the well-known Ramsey property with a dual
form of it, the so called dual-Ramsey property (which was suggested
first by Carlson and Simpson). Even if the two properties are
different, it can be shown that all classical results known for the
Ramsey property also hold for the dual-Ramsey property. We will also
show that the dual-Ramsey property is closed under a generalized
Suslin operation (the similar result for the Ramsey property was
proved by Matet). Further we compare two notions of forcing, the
Mathias forcing and a dual form of it, and will give some symmetries
between them. Finally we give some relationships between the
dual-Mathias forcing and the dual-Ramsey property.