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 Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Congruence modular and congruence distributive varieties can be characterizedby the existence of sequences of Gumm and J\'onsson terms, respectively. Suchsequences have variable lengths, in general. It is immediate from the aboveparagraph that there is a variety with Gumm terms but without J\'onsson terms.We prove the quite unexpected result that, on the other hand, if some varietyhas both kinds of terms, then the minimal lengths of the sequences differ atmost by $1$. It follows that every $r$-modular congruence distributive varietyis $r^2-r+2$-distributive.

The Gumm level equals the alvin level in congruence distributive varieties