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

We generalize the celebrated results of Bernhard Riemann and Gaston Darboux:we give necessary and sufficient conditions for a bilinear form to be flat.More precisely, we give explicit necessary and sufficient conditions for atensor field of type (0,2) which is not necessary symmetric or skew-symmetric,and is possibly degenerate, to have constant entries in a local coordinatesystem.

Bernhard Riemann 1861 revisited: existence of flat coordinates for an arbitrary bilinear form