Spontaneous Breaking of Lepton Number and Cosmological Domain Wall
  Problem
  We show that if global lepton number symmetry is spontaneously broken in a
post inflation epoch, then it can lead to the formation of cosmological domain
walls. This happens in the well-known "Majoron paradigm" for neutrino mass
generation. We propose some realistic examples which allow spontaneous lepton
number breaking to be safe from such domain walls.
