### 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

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

# 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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