Abstract
We prove that a strong solution u to the Navier-Stokes equations on (0, T) can be extended if either u ∈ L
θ
(0, T;
U
˙
∞
,
1
/
θ
,
∞
−
α
$\begin{array}{}
\displaystyle
\dot{U}^{-\alpha}_{\infty,1/\theta,\infty}
\end{array}$
) for 2/θ + α = 1, 0 < α < 1 or u ∈ L
2(0, T;
V
˙
∞
,
∞
,
2
0
$\begin{array}{}
\displaystyle
\dot{V}^{0}_{\infty,\infty,2}
\end{array}$
), where
U
˙
p
,
β
,
σ
s
$\begin{array}{}
\displaystyle
\dot{U}^{s}_{p,\beta,\sigma}
\end{array}$
and
V
˙
p
,
q
,
θ
s
$\begin{array}{}
\displaystyle
\dot{V}^{s}_{p,q,\theta}
\end{array}$
are Banach spaces that may be larger than the homogeneous Besov space
B
˙
p
,
q
s
$\begin{array}{}
\displaystyle
\dot{B}^{s}_{p,q}
\end{array}$
. Our method is based on a bilinear estimate and a logarithmic interpolation inequality.