Happy Families and Their Relatives
- 👤 Speaker: Halbeisen, L J (ETH Zrich)
- 📅 Date & Time: Thursday 27 August 2015, 11:30 - 12:30
- 📍 Venue: Seminar Room 1, Newton Institute
Abstract
We first recall the notion of $ happy$$ families$ as well as their combinatorial properties. Then we present some families which are related to $ happy$$ families$ and investigate $ Mathias$$ forcing$ restricted to these families. In the second part we show the relation between $it Mathias$$ forcing$ and the $ Ramsey$$ property$ and discuss the still open problem whether one can take $ Mathias’$$ inaccessible$ away. In the last part, we sketch Shelah’s construction of a model of ZFC in which there are exactly $ 70$$ happy$$ ultrafilters$.
Series This talk is part of the Isaac Newton Institute Seminar Series series.
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Halbeisen, L J (ETH Zrich)
Thursday 27 August 2015, 11:30-12:30