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### Recent blog posts

- A strong form of König’s lemma October 21, 2017
- 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

### Keywords

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

# Tag Archives: Mandelbrot set

## A natural Mandelbrot set

Chris Hadfield is a Canadian astronaut, with a very high-profile twitter account. He posts there beautiful photos everyday, and I (plus half a million followers) enjoy it very much. Today, Chris posted the following picture: and I find it quite … Continue reading