On Wave Dark Matter, Shells in Elliptical Galaxies, and the Axioms of
  General Relativity
  This paper is a sequel to the author's paper entitled "On Dark Matter, Spiral
Galaxies, and the Axioms of General Relativity" [arXiv:1004.4016] which
explored a geometrically natural axiomatic definition for dark matter modeled
by a scalar field satisfying the Einstein-Klein-Gordon wave equations which,
after much calculation, was shown to be consistent with the observed spiral and
barred spiral patterns in disk galaxies. We give an update on where things
stand on this "wave dark matter" model of dark matter (aka scalar field dark
matter and boson stars), an interesting alternative to the WIMP model of dark
matter, and discuss how it has the potential to help explain the long-observed
interleaved shell patterns, also known as ripples, in the images of elliptical
galaxies.
