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 Tools annual

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 monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We present a simple and fast algorithm for the computation of thecoefficients of the expansion of a function f(cos u) in ultraspherical(Gegenbauer) polynomials. We prove that these coefficients coincide with theFourier coefficients of an Abel-type transform of the function f(cos u). Thisallows us to fully exploit the computational efficiency of the Fast FourierTransform, computing the first N ultraspherical coefficients in just O (N log_2N) operations.

The expansion in ultraspherical polynomials: a simple procedure for the fast computation of the ultraspherical coefficients