  We consider the vanishing viscosity problem for solutions of the
Navier-Stokes equations with Navier boundary conditions in the half-space. We
lower the currently known conormal regularity needed to establish that the
inviscid limit holds. Our requirement for the Lipschitz initial data is that
the first four conormal derivatives are bounded along with two for the
gradient. In addition, we establish a new class of initial data for the local
existence and uniqueness for the Euler equations in the half-space or a channel
for initial data in the conormal space without conormal requirements on the
gradient.
