Archives
Keywords
Subnormal ideal incompactness Successor of Regular Cardinal Dowker space Ascending path Monotonically far Fast club Singular cofinality Subtle tree property Ramsey theory over partitions transformations positive partition relation SNR Analytic sets specializable Souslin tree Postprocessing function Parameterized proxy principle Distributive tree Singular cardinals combinatorics Subtle cardinal coloring number Almost Souslin ZFC construction Dushnik-Miller Fodor-type reflection Commutative cancellative semigroups Strong coloring Luzin set Countryman line Singular Density Greatly Mahlo Erdos Cardinal PFA(S)[S] perfectly normal countably metacompact Ulam matrix Forcing with side conditions nonmeager set xbox C-sequence Large Cardinals Knaster and friends Reflecting stationary set Foundations Universal Sequences OCA Diamond Amenable C-sequence super-Souslin tree strongly bounded groups Souslin Tree stationary reflection Poset Axiom R Chromatic number Vanishing levels Prevalent singular cardinals Kurepa Hypothesis GMA higher Baire space Sigma-Prikry Small forcing Successor of Singular Cardinal diamond star Sakurai's Bell inequality approachability ideal Lipschitz reduction Microscopic Approach PFA very good scale Hereditarily Lindelöf space b-scale Subadditive reflection principles Knaster indecomposable filter polarized partition relation Minimal Walks Slim tree Strongly Luzin set Hedetniemi's conjecture 54G20 ccc Whitehead Problem Club Guessing Iterated forcing Well-behaved magma Chang's conjecture full tree Nonspecial tree O-space Open Access HOD Uniformization middle diamond square weak diamond Diamond-sharp Rock n' Roll weak Kurepa tree Reduced Power tensor product graph sap AIM forcing Intersection model Coherent tree Absoluteness free Souslin tree Filter reflection Precaliber Interval topology on trees Jonsson cardinal Uniformly coherent stationary hitting Was Ulam right? Ineffable cardinal S-Space Weakly compact cardinal Commutative projection system Mandelbrot set Rado's conjecture unbounded function Prikry-type forcing club_AD Cardinal Invariants Entangled linear order Non-saturation Ostaszewski square Diamond for trees stick Ascent Path Square-Brackets Partition Relations Aronszajn tree Forcing Axioms Local Club Condensation. Sierpinski's onto mapping principle Respecting tree Hindman's Theorem Almost-disjoint family Martin's Axiom Rainbow sets Almost countably chromatic Fat stationary set Generalized Clubs Closed coloring free Boolean algebra projective Boolean algebra Antichain regressive Souslin tree square principles Generalized descriptive set theory Uniformly homogeneous L-space weak square Forcing Cardinal function Strongly compact cardinal Selective Ultrafilter Erdos-Hajnal graphs P-Ideal Dichotomy Partition Relations Constructible Universe Shelah's Strong Hypothesis Cohen real
Tag Archives: Commutative projection system
Ketonen’s question and other cardinal sins
Joint work with Zhixing You and Jiachen Yuan. Abstract. Answering a question of Ketonen from the late 1970’s, it is proved that a weakly compact cardinal carrying an indecomposable ultrafilter need not be measurable. The result is obtained by analyzing … Continue reading
