  One of the fundamental facts of condensed matter physics is that sufficient
amount of disorder always turns a Fermi liquid metal into an Anderson
insulator: a compressible, but non-conducting phase of matter. Recently,
topological semimetals have emerged as another way a metallic phase may be
realized. In this paper we point out that, unlike ordinary metals, at least
some topological semimetals are immune to localization, provided certain
conditions are satisfied. We present several physical arguments, based on
diagrammatic perturbation theory and Keldysh field theory, as well as domain
wall network construction, to back up this claim.
