New posts in filters

How many ultrafilters there are in an infinite space?

Hausdorff spaces from filters

A layman's motivation for non-standard analysis and generalised limits

A Prime $\mathcal P$-filter is contained in a unique $\mathcal P$-ultrafilter?

Ultrafilter Lemma and Alexander subbase theorem

Every net has an ultranet as subnet: direct proof

Ultrafilters and self-injections

Simple proof about prime filters.

ultrafilters as linear orders

Uniqueness of hyperreals contructed via ultrapowers

Relation between a filter and its complement being an ideal.

How can an ultrafilter be considered as a finitely additive measure?

Cauchy filters in metric spaces

Nonisomorphic free ultrafilters on $\omega$

Injective function and ultrafilters

Sum and product of ultrafilters

every non-principal ultrafilter contains a cofinite filter.

Why were filters and nets in topology named filters and nets?

Lemma 2.20 of Kunen

Can you get a non-principal ultrafilter on N using Choice but 'avoiding' Zorn's Lemma?