### Archives

### Recent blog posts

- Prikry forcing may add a Souslin tree June 12, 2016
- The reflection principle $R_2$ May 20, 2016
- Prolific Souslin trees March 17, 2016
- Generalizations of Martin’s Axiom and the well-met condition January 11, 2015
- Many diamonds from just one January 6, 2015
- Happy new jewish year! September 24, 2014
- Square principles April 19, 2014
- Partitioning the club guessing January 22, 2014

### Keywords

square principles HOD Non-saturation Cardinal Invariants Knaster stationary hitting OCA Jonsson cardinal sap diamond star super-Souslin tree S-Space Club Guessing Distributive tree Weakly compact cardinal weak diamond Poset Chang's conjecture Uniformization Commutative cancellative semigroups polarized partition relation Minimal Walks Universal Sequences Generalized Clubs Almost countably chromatic 20M14 Souslin Tree Foundations PFA(S)[S] Diamond Uniformly coherent Square-Brackets Partition Relations Nonspecial tree Parameterized proxy principle Axiom R stationary reflection Postprocessing function Sakurai's Bell inequality Cohen real Almost-disjoint famiy Forcing Erdos Cardinal middle diamond Rainbow sets Cardinal function Fodor-type reflection Prikry-type forcing tensor product graph Dushnik-Miller Forcing Axioms xbox coloring number L-space Stevo Todorcevic very good scale Rado's conjecture Fast club Large Cardinals 11P99 projective Boolean algebra Antichain Singular coﬁnality Successor of Singular Cardinal Hindman's Theorem Singular Density 05A17 Slim tree Rock n' Roll Martin's Axiom Constructible Universe Fat stationary set Hereditarily Lindelöf space Luzin set Hedetniemi's conjecture Almost Souslin Coherent tree P-Ideal Dichotomy Microscopic Approach Singular cardinals combinatorics Successor of Regular Cardinal Aronszajn tree Absoluteness Erdos-Hajnal graphs ccc b-scale Reduced Power PFA Chromatic number Partition Relations weak square Selective Ultrafilter Whitehead Problem Shelah's Strong Hypothesis square approachability ideal Prevalent singular cardinals reflection principles Kurepa Hypothesis Ostaszewski square Mandelbrot set Ascent Path Small forcing free Boolean algebra incompactness

# Category Archives: Notes

## Shelah’s solution to Whitehead’s problem

Whitehead problem notes in hebrew : Table of contents Chapter 0 Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 References

## Infinite Combinatorial Topology

Back in 2005, as a master student, I attended a course by Boaz Tsaban, entitled “Infinite Combinatorial Topology”. A friend and I decided to produce lecture notes, but in a somewhat loose sense, that is: we sometimes omit material given … Continue reading

Posted in Notes
Tagged b-scale, Cardinal function, Cardinal Invariants, Hereditarily Lindelöf space
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