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 describe the norm-closures of the set $\mathfrak{C}_{\mathfrak{E}}$ ofcommutators of idempotent operators and the set $\mathfrak{E} - \mathfrak{E}$of differences of idempotent operators acting on a finite-dimensional complexHilbert space, as well as characterising the intersection of the closures ofthese sets with the set $\mathcal{K}(\mathcal{H})$ of compact operators actingon an infinite-dimensional, separable Hilbert space. Finally, we characterisethe closures of the set $\mathfrak{C}_{\mathfrak{P}}$ of commutators oforthogonal projections and the set $\mathfrak{P} - \mathfrak{P}$ of differencesof orthogonal projections acting on an arbitrary complex Hilbert space.

Around the closures of the set of commutators and the set of differences of idempotent elements of $\mathcal{B}(\mathcal{H})$