[06X]Prerequisites:[06P]↺↻.Let \((X,≤)\) be a directed set, and \(Y⊆ X\) cofinal: show that \((Y,{≤}_{|{Y}})\) is a directed set.
Similarly, if \((X,≤)\) is filtering, show that \((Y,{≤}_{|{Y}})\) it is filtering.
