Cofinal function
= Cofinal function
A function $f:\beta\to\alpha$ between ordinals is cofinal when its range is unbounded in $\alpha$: for every $\gamma<\alpha$ some $\xi<\beta$ satisfies $\gamma\leq f(\xi)$.
= Cofinal function
A function $f:\beta\to\alpha$ between ordinals is cofinal when its range is unbounded in $\alpha$: for every $\gamma<\alpha$ some $\xi<\beta$ satisfies $\gamma\leq f(\xi)$.