Global boundedness of solutions of degenerate and non-uniform parabolic equations

Let $2 \le N\in\mathbb{N}$, $Ω$ be a bounded open in $\mathbb{R}^{N}$, $T\in (0,\infty)$, $Q=Ω\times (0,T)$, $u$ be a weak solution of parabolic equation $\displaystyle \frac{\partial u}{\partial t} -Lu= f$, where $L$ is an elliptic operator on a space of functions on $Q$. The coefficients of $L$ may not be bounded, not strictly nor uniformly elliptic, and not of Muckenhoupt type. We obtain global boundedness of $u$. Our result can be applied to $u$, which may vanish on $(A\times (0,T))\cup (Ω\times \{0\})$ of the boundary of $Q$ and is free outside this set.