(This is the fourth lecture in Stevo Todorcevic’s Forcing class, held in the fall of 2012. You can find the third lecture here. Quotes by Stevo are in dark blue; some are deep, some are funny, some are paraphrased so use your judgement. As always I appreciate any type of feedback, including reporting typos, in the comments below.)
- We look at the real reason that regular open algebras don’t collapse to .
- Show there is a -linked, non -centred poset of size .
- Introduce the cardinal , related to Chang’s Conjecture.
- Introduce the idea of a functor on ccc posets.