Products of conjugacy classes in ${\text{SL}}_2(k)$ and ${\text{PSL}}_2(k)$

Harish Kishnani, Rijubrata Kundu, Sumit Chandra Mishra

Let $k$ be a field with $u$-invariant $\le 2$. Assume further that $k$ is not quadratically closed, $\mathsf{char}(k)\ne 2$ and $|k|\ge 5$. It is known that the covering number o…