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

Let   Z   be a quadratic hypersurface ofP  n    (  R  )defined over   Q   containing points whose coordinates are linearly independent over   Q  . We show that, among these points, the largest exponent of uniform rational approximation is the inverse    1  /  ρ    of an explicit Pisot number    ρ  <  2    depending only on   n   if the Witt index (over   Q  ) of the quadratic form   q   defining   Z   is at most 1, and that it is equal to 1 otherwise. Furthermore, there are points of   Z   which realize this maximum. They constitute a countably infinite set in the first case, and an uncountable set in the second case. The proof for the upper bound    1  /  ρ    uses a recent transference inequality of Marnat and Moshchevitin. In the case    n  =  2   , we recover results of the second author while for    n  >  2   , this completes recent work of Kleinbock and Moshchevitin.

Rational approximation to real points on quadratic hypersurfaces