  Recent progress seems to suggest that one must modify General Relativity (GR)
to stably violate the null energy condition and avoid the cosmological
singularity. However, with the higher-order derivative operators of scalar
field (a subclass of the degenerate higher-order scalar-tensor theory), we show
that at energies well below the Planck scale, fully stable nonsingular
cosmologies can actually be implemented within GR.
