# Choice principles and lift lemmas

@inproceedings{Ern2017ChoicePA, title={Choice principles and lift lemmas}, author={M. Ern{\'e}}, year={2017} }

We show that in ZF set theory without choice, the Ultrafilter Principle (UP) is equivalent to several compactness theorems for Alexandroff discrete spaces and to Rudin’s Lemma, a basic tool in topology and the theory of quasicontinuous domains. Important consequences of Rudin’s Lemma are various lift lemmas, saying that certain properties of posets are inherited by the free unital semilattices over them. Some of these principles follow not only from UP but also from DC, the Principle of… Expand

#### 2 Citations

Categories of Locally Hypercompact Spaces and Quasicontinuous Posets

- Computer Science, Mathematics
- Appl. Categorical Struct.
- 2018

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