Under the Axiom of Determinacy, the least uncountable cardinal omega_1 behaves like a large cardinal. We will present a theorem due to Woodin saying that from a strong form of determinacy, namely AD_R + "Theta is regular," one can force the Axiom of Choice together with the statement "there is an omega_1-dense ideal on omega_1." In essence, omega_1 retains a trace of its "large cardinal" nature that is consistent with AC.
We complete our introduction to the principle ISP and its relatives as well as their connections to supercompact cardinals and the proper forcing axiom. As a consequence of our analysis we give a proof that all known forcing constructions of models satisfying PFA require very large cardinals.
We continue with an introduction to the principle ISP and its relatives as well as their connections to supercompact cardinals and the proper forcing axiom. In particular, we prove that PFA implies ISP.
We present some basic applications of the Proper Forcing Axiom: Square inaccessibility of all cardinals above \omega_1, and the tree property at \omega_2.
Set theory studies reflection principles of different forms. The talk will discuss the role of stationary reflection and threadability in the core model induction. I will not presuppose any serious knowledge of inner model theory, though.
We survey several well-known direct consequences of very large cardinal axioms. In particular we intend to cover SCH (Solovay), the failure of the approachability property (Shelah), and the failure of Not So Very Weak Square (Foreman--Magidor). If time permits, we will discuss a characterization of strong compactness due to Ketonen or the tree property (Magidor-Shelah).
We survey several well-known direct consequences of very large cardinal axioms. In particular we intend to cover SCH (Solovay), the failure of the approachability property (Shelah), and the failure of Not So Very Weak Square (Foreman--Magidor). If time permits, we will discuss a characterization of strong compactness due to Ketonen or the tree property (Magidor-Shelah).