  We identify a class of measure-valued solutions of the barotropic Euler
system on a general (un-bounded) spatial domain as a vanishing viscosity limit
for the compressible Navier-Stokes system. Then we establish the weak
(measure-valued)-strong uniqueness principle, and, as a corollary, we obtain
strong convergence to the Euler system on the lifespan of the strong solution.

Analysis of PDEs