Kappa-tree
= Kappa-tree
{title2=$\kappa\text{-tree}$}
For a regular uncountable <cardinal number> $\kappa$, a <set-theoretic tree> of height $\kappa$ with nonempty levels of <cardinality> less than $\kappa$. The regular-height convention is important for the <unbounded-extension kernel of a regular tree>.