例句與造句

1. But does adding countable compactness ensure the Lindelof condition?
2. I find it amazing that an'unrelated axiom'( countable compactness ) can make finding a counterexample a lot harder.
3. These metric spaces have some nice properties like : in a metric space compactness, sequential compactness and countable compactness are equivalent etc . These properties may not, however, hold so easily if the distance function is taken in an arbitrary ordered field, instead of in \ scriptstyle \ mathbb R.
4. It's difficult to find countable compactness in a sentence. 用countable compactness造句挺難的