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/

Zendy Plus

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

Zendy Tools

Zendy Open

A set of proper subgroups is a covering for a group if its union is the wholegroup. The minimal number of subgroups needed to cover $G$ is called thecovering number of $G$, denoted by $\sigma(G)$. Determining $\sigma(G)$ is anopen problem for many non-solvable groups. For symmetric groups $S_n$, Mar\'otidetermined $\sigma(S_n)$ for odd $n$ with the exception of $n=9$ and gaveestimates for $n$ even. In this paper we determine $\sigma(S_n)$ for $n = 8$,$9$, $10$ and $12$. In addition we find the covering number for the Mathieugroup $M_{12}$ and improve an estimate given by Holmes for the Janko group$J_1$.

On the Covering Number of Small Symmetric Groups and Some Sporadic Simple Groups