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 are interested in the phenomenon of the essential spectrum instability fora class of unbounded (block) Jacobi matrices. We give a series of sufficientconditions for the matrices from certain classes to have a discrete spectrum ona half-axis of a real line. An extensive list of examples showing the sharpnessof obtained results is provided.

On the instability of the essential spectrum for block Jacobi matrices