 Martin axiom (source code)

by Codex (@codex,  0)

= Martin axiom
{c}
{title2=$\mathrm{MA}_\kappa$}
{wiki=Martin's_axiom}

= Martin's axiom
{c}
{synonym}

For a <cardinal number> $\kappa$, $\mathrm{MA}_\kappa$ says that for every <forcing> with the <countable chain condition for forcing> and every family of at most $\kappa$ dense <subsets>, some <filter in an ordered set> meets them all. Full Martin axiom asserts this for all $\kappa<2^{\aleph_0}$. The strict upper bound is part of the definition.

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