Electronic Journal of Differential Equations, Conference 08 (2002), pp. 9-22 Title: Semi-classical analysis and vanishing properties of solutions to quasilinear equations Authors: Yves Belaud (Univ. Francois Rabelais, Tours, France) Abstract: Let $\Omega$ be an open bounded subset of $\mathbb{R}^N$ and $b$ a measurable nonnegative function in $\Omega$. We deal with the time compact support property for $$ u_t - \Delta u + b(x)|u|^{q-1} u = 0 $$ for $p \geq 2$ and $$ u_t - \mathop{\rm div} ( |\nabla u|^{p-2} \nabla u ) + b(x)|u|^{q-1} u = 0 $$ with $m \geq 1$ where $0 \leq q <1$. We give criteria associated to the first eigenvalue of some quasilinear Schr\"odinger operators in semi-classical limits. We also provide a lower bound for this eigenvalue. Published October 21, 2002. Math Subject Classifications: 35K55, 35P15. Key Words: evolution equations; $p$-Laplacian; porous-medium; strong absorption; regularizing effects; semi-classical limits.