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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We complete the classical Schoenberg representation theorem for radialpositive definite functions. We apply this result to study spectral propertiesof self-adjoint realizations of two- and three-dimensional Schr\"odingeroperators with point interactions on a finite set. In particular, we prove thatany realization has purely absolutely continuous non-negative spectrum.

Radial positive definite functions and spectral theory of the Schr\"odinger operators with point interactions