DOI: 10.68381/jca33001 ISSN: 0944-6532

A Generalization of the Stampacchia Lemma and Applications

Hongya Gao, Jiaxiang Zhang, Hongyan Ma

We present a generalization of Stampacchia Lemma and give applications to regularity property of weak and entropy solutions of degenerate elliptic equations of the form

\begin{cases} -\text{div} (a(x,u(x)) Du (x)) =f(x), & \text { in } \Omega, \\[1mm] u(x)=0, & \text { on } \partial \Omega, \end{cases} { − div ( a ( x , u ( x ) ) D u ( x ) ) = f ( x ) ,  in  Ω , u ( x ) = 0 ,  on  ∂ Ω ,
where
\displaystyle\frac {\alpha}{(1+|u|) ^\theta} \le a(x,s)\le \beta α ( 1 + ∣ u ∣ ) θ ≤ a ( x , s ) ≤ β
with
0<\alpha \le \beta <\infty 0 < α ≤ β < ∞
and
0\le \theta <1 0 ≤ θ < 1
. The method to derive regularity seems to be simpler than the classical ones.