EDB — 06X

Exercises

1. [06X]Prerequisites:[06P]↺↻.Let $(X,\le )$ be a directed set, and $Y\subseteq X$ cofinal: show that $(Y,{\le }_{|Y})$ is a directed set.

   Similarly, if $(X,\le )$ is filtering, show that $(Y,{\le }_{|Y})$ it is filtering.