Global monopoles can change Universe's topology
  If the Universe undergoes a phase transition, at which global monopoles are
created or destroyed, topology of its spatial sections can change. More
specifically, by making use of Myers' theorem, we show that, after a transition
in which global monopoles form, spatial sections of a spatially flat Universe
become finite and closed. This implies that global monopoles can change
topology of Universe's spatial sections (from infinite and open to finite and
closed). We emphasize that global monopoles cannot alter topology of the
space-time manifold.
