English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We show that there exists an ultrafilter U in the set N of natural numbers such that the cofinality of the U-ultrapower N N/U equals cof(d), where d is the minimal cardinality of a dominating subfamily of N N. More over, the coinitiality of the family of finite-to-one functions in this ultrapower is also cof(d). If c=d, then U may be taken to be a P-point

Cofinalities of countable ultraproducts: the existence theorem.