Stationary set
= Stationary set
{title2=$S\cap C\ne\varnothing\text{ for every club }C$}
A subset of a regular uncountable <cardinal number> $\kappa$ is stationary if it meets every <club set> in $\kappa$. Intersecting a stationary set with a <club set> preserves stationarity. Every member of the <club filter> is stationary. At a regular infinite $\theta<\kappa$, the <stationarity of ordinals of prescribed cofinality> supplies important examples.