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

In this short note we show that non-negative Ricci curvature is not preservedunder Ricci flow for closed manifolds of dimensions four and above,strengthening a previous result of Knopf in \cite{K} for complete non-compactmanifolds of bounded curvature. This brings down to four dimensions a similarresult B\"ohm and Wilking have for dimensions twelve and above, \cite{BW}.Moreover, the manifolds constructed here are \Kahler manifolds and relate to aquestion raised by Xiuxiong Chen in \cite{XC}, \cite{XCL}.

Non-negative Ricci curvature on closed manifolds under Ricci flow