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### 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

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

# Tag Archives: 06E05

## Openly generated Boolean algebras and the Fodor-type reflection principle

Joint work with Sakaé Fuchino. Abstract: We prove that the Fodor-type Reflection Principle (FRP) is equivalent to the assertion that any Boolean algebra is openly generated if and only if it is $\aleph _2$-projective. Previously it was known that this … Continue reading