Improved DHOST Genesis
  We improve the DHOST Genesis proposed in \cite{Ilyas:2020zcb}, such that the
near scale invariant scalar power spectrum can be generated from the model
itself, without involking extra mechanism like a string gas. Besides, the
superluminality problem of scalar perturbation plagued in \cite{Ilyas:2020zcb}
can be rescued by choosing proper DHOST action.
