[Papers]NSE, $u$, Lorentz space [Bosia-Pata-Robinson, JMFM, 2014]
$$\bex \bbu\in L^p(0,T;L^{q,\infty}),\quad \frac{2}{p}+\frac{3}{q}=1,\quad 3<q\leq\infty. \eex$$ or $$\bex \sen{\bbu}_{L^{p,\infty}(0,T;L^{q,\infty})}\leq \ve,\quad \frac{2}{p}+\frac{3}{q}=1,\quad