Local boundedness for $ p $-Laplacian with degenerate coefficients

We study local boundedness for subsolutions of nonlinear nonuniformly elliptic equations whose prototype is given by $ \nabla \cdot (\lambda |\nabla u|^{p-2}\nabla u) = 0 $, where the variable coefficient $ 0\leq\lambda $ and its inverse $ \lambda^{-1} $ are allowed to be unbounded. Assuming certain integrability conditions on $ \lambda $ and $ \lambda^{-1} $ depending on $ p $ and the dimension, we show local boundedness. Moreover, we provide counterexamples to regularity showing that the integrability conditions are optimal for every $ p > 1 $.