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/

Zendy Plus

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

Zendy Tools

Zendy Open

We show that 4-dimensional Riemannian manifolds which satisfy the Raki\'cduality principle are Osserman (i.e. the eigenvalues of the Jacobi operator areconstant), thus both conditions are equivalent.

Equivalence between the Osserman condition and the Raki\'c duality principle in dimension four