### 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

Postprocessing function Selective Ultrafilter free Boolean algebra coloring number Small forcing 11P99 Shelah's Strong Hypothesis approachability ideal Singular coﬁnality Chromatic number Minimal Walks Antichain Reduced Power Distributive tree Almost countably chromatic Non-saturation Kurepa Hypothesis projective Boolean algebra square Hindman's Theorem diamond star b-scale 05D10 Dushnik-Miller Hereditarily Lindelöf space 05A17 Rock n' Roll Prikry-type forcing weak diamond Diamond Ostaszewski square middle diamond ccc Successor of Regular Cardinal Poset Uniformly coherent very good scale Commutative cancellative semigroups PFA(S)[S] Knaster Uniformization Cardinal function Club Guessing Constructible Universe Successor of Singular Cardinal Souslin Tree polarized partition relation Coherent tree Martin's Axiom square principles xbox Rainbow sets Square-Brackets Partition Relations Almost Souslin Whitehead Problem Sakurai's Bell inequality Mandelbrot set S-Space Forcing Axioms reflection principles Absoluteness stationary reflection Chang's conjecture Rado's conjecture Cardinal Invariants Slim tree Forcing Large Cardinals Parameterized proxy principle Aronszajn tree Jonsson cardinal tensor product graph Partition Relations Prevalent singular cardinals Hedetniemi's conjecture Almost-disjoint famiy Fat stationary set stationary hitting OCA Erdos Cardinal Weakly compact cardinal P-Ideal Dichotomy Foundations L-space Singular cardinals combinatorics Fast club Axiom R Microscopic Approach Stevo Todorcevic Cohen real incompactness Generalized Clubs Ascent Path HOD sap Nonspecial tree PFA 20M14 weak square Universal Sequences Singular Density Fodor-type reflection Erdos-Hajnal graphs

# 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