In a recent work of the author, a parabolic extension of the elliptic Ogawa
type inequality has been established. This inequality is originated from the
Brezis-Gallouet-Wainger logarithmic type inequalities revealing Sobolev
embeddings in the critical case. In this paper, we improve the parabolic
version of Ogawa inequality by allowing it to cover not only the class of
functions from Sobolev spaces, but the wider class of Holder continuous
functions.
In this paper, we show a parabolic version of the Ogawa type inequality in
Sobolev spaces. Our inequality provides an estimate of the $L^{\infty}$ norm of
a function in terms of its parabolic $BMO$ norm, with the aid of the square
root of the logarithmic dependency of a higher order Sobolev norm. The proof is
mainly based on the Littlewood-Paley decomposition and a characterization of
parabolic $BMO$ spaces.