Waring's problem for fields
W. J. Ellison · Acta Arithmetica · 2013
If $\textbf {K}$ is a field, denote by $P(\textbf {K}, k)$ the $a\in \textbf {K}$ which are sums of $k$th powers of elements of $\textbf {K}$, by $P^{+}(\textbf {K}, k)$ the set of $a\in \textbf {K}$ which are sums of $k$th powers of totally positive elem