Archives
Keywords
Respecting tree Dowker space Amenable C-sequence Erdos Cardinal Constructible Universe polarized partition relation Almost Souslin Reflecting stationary set Souslin Tree Ascent Path Cohen real Subadditive Antichain PFA Postprocessing function Square-Brackets Partition Relations Diamond for trees coloring number PFA(S)[S] Whitehead Problem Microscopic Approach Uniformly coherent Almost countably chromatic Forcing Ulam matrix Strongly Luzin set Coherent tree b-scale Partition Relations reflection principles SNR Lipschitz reduction Foundations Diamond free Souslin tree stick Selective Ultrafilter Singular Density Sigma-Prikry Erdos-Hajnal graphs Hereditarily Lindelöf space Closed coloring Ostaszewski square approachability ideal Weakly compact cardinal super-Souslin tree strongly bounded groups Minimal Walks stationary reflection Slim tree S-Space Parameterized proxy principle positive partition relation Fast club Open Access stationary hitting Countryman line incompactness middle diamond ccc Rainbow sets L-space Jonsson cardinal Subtle tree property 54G20 indecomposable ultrafilter Reduced Power Axiom R weak Kurepa tree Sakurai's Bell inequality Knaster and friends Large Cardinals O-space free Boolean algebra Filter reflection ZFC construction countably metacompact OCA Nonspecial tree Analytic sets Generalized descriptive set theory Rock n' Roll HOD square Non-saturation Chang's conjecture Strongly compact cardinal Hedetniemi's conjecture higher Baire space Cardinal function Vanishing levels projective Boolean algebra Luzin set Cardinal Invariants Rado's conjecture Iterated forcing Ramsey theory over partitions Singular cardinals combinatorics Diamond-sharp Fat stationary set Successor of Singular Cardinal Prevalent singular cardinals GMA Almost-disjoint family specializable Souslin tree Precaliber C-sequence Greatly Mahlo Local Club Condensation. Kurepa Hypothesis Absoluteness Commutative cancellative semigroups very good scale Uniformly homogeneous Knaster Intersection model Subnormal ideal P-Ideal Dichotomy Chromatic number Generalized Clubs Successor of Regular Cardinal square principles Shelah's Strong Hypothesis unbounded function Distributive tree xbox Ineffable cardinal full tree Universal Sequences weak square tensor product graph Mandelbrot set Strong coloring Commutative projection system Uniformization Poset AIM forcing Dushnik-Miller Singular cofinality Fodor-type reflection Club Guessing diamond star transformations weak diamond Aronszajn tree Prikry-type forcing Subtle cardinal Martin's Axiom Was Ulam right? Hindman's Theorem Small forcing regressive Souslin tree nonmeager set Well-behaved magma Forcing Axioms Sierpinski's onto mapping principle sap club_AD
Tag Archives: 20E15
A Shelah group in ZFC
Joint work with Márk Poór. Abstract. In a paper from 1980, Shelah constructed an uncountable group all of whose proper subgroups are countable. Assuming the continuum hypothesis, he constructed an uncountable group
Posted in Groups, Publications
Tagged 03E02, 03E75, 20A15, 20E15, 20F06, Jonsson cardinal, Strong coloring, strongly bounded groups, Subadditive, ZFC construction
3 Comments
