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 consider the eigenvalue problem u′′+λu+p(x)u = 0 in (0, π), u(0) = u(π) = 0, where p ∈ L1(0, π) keeps a fixed sign and ‖p‖L1 > 0, and we obtain some lower and upper bounds for ‖p‖L1 in terms of its nonnegative eigenvalues λ. Two typical results are: (1) ‖p‖L1 > √ λ | sin√λ π| if λ > 1 and is not the square of a positive integer; (2) ‖p‖L1 ≤ 16/π if λ = 0 is the smallest eigenvalue.

Eigenvalues of a Sturm-Liouville problem and inequalities of Lyapunov type