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 Tools annual

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 Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Hjorth has introduced a Scott analysis for general Polish group actions, andhas asked whether his notion of rank satisfies a boundedness principle similarto the one of Scott rank - namely, the orbit equivalence relation is Borel ifand only if Hjorth ranks are bounded.  We present the principles of Hjorth analysis and Hjorth rank, and answerHjorth's question positively. From that we get a positive answer to aconjecture due to Hjorth - for every limit ordinal $\alpha$ , the set ofelements whose orbit is of complexity less than $\alpha$ is a Borel set. Wethen show Nadel's theorem for Hjorth rank - the rank of $x$ is no more than$\omega_{1}^{ck(x)}$.

Hjorth Analysis of General Polish Group Actions