One dimensional oscillatory integrals of the type $\int^\infty _0 \xi ^\alpha \rm\exp \big[it(p(\xi )-\xi x)\big]\rm {d}\xi $ are considered, where $p(\xi )$ is a real polynomial of degree $m\geq 3$. Long-time decay and global smoothing estimates are established, as well as short-time behavior as $t\to 0$. The results are applied to the fundamental solutions of a class of linearized Kadomtsev-Petviashvili equations with higher dispersion

We prove that any weak harmonic map flow $u$ from a Riemannian surface to a general manifold is smooth, provided that $\sup_{0\le t<\infty}E(u(\cdot,t))$ is sufficiently small.

The asymptotic behavior of eigenvalues and eigenfunctions of $p$-Laplace operator is investigated. We obtain (I) the best constant of $L^\infty$-Poincaré's inequality, and (II) a limit equation which the limits of eigenvalues and eigenfunctions satisfy in a weak sense.

We study a non local evolution and define the interface in terms of a local equilibrium condition. We prove that in a diffusive scaling limit the local equilibrium condition propagates in time thus defining an interface evolution which is given by a motion by mean curvature. The analysis extend through all times before the appearance of singularities.

In this paper we establish new Caccioppoli type estimates for second order PDEs. With the aid of these estimates we identify removable singularities of $A$-harmonic functions.

We prove local optimality principles for viscosity super and subsolutions of Hamilton-Jacobi equations with unbounded ingredients. We apply these results to characterize the (possibly multiple) discontinuous solutions of mixed Dirichlet and constrained boundary value problems.