Emergent Universe and Genesis from the DHOST Cosmology
  In this article, we present an emergent universe scenario that can be derived
from DHOST cosmology. The universe starts asymptotically Minkowski in the far
past just like the regular Galileon Genesis, but evolves to a radiation
dominated period at the late stage, and therefore, the universe has a graceful
exit which is absent in the regular Galileon Genesis. We analyze the behavior
of cosmological perturbations and show that both the scalar and tensor modes
are free from the gradient instability problem. We further analyze the
primordial scalar spectrum generated in various situations and discuss whether
a scale invariance can be achieved.
