Unimodular Mimetic $F(R)$ Inflation
  We propose the unimodular-mimetic $F(R)$ gravity theory, to resolve
cosmological constant problem and dark matter problem in a unified geometric
manner. We demonstrate that such a theory naturally admits accelerating
universe evolution. Furthermore, we construct unimodular-mimetic $F(R)$
inflationary cosmological scenarios compatible with the Planck and
BICEP2/Keck-Array observational data. We also address the graceful exit issue,
which is guaranteed by the existence of unstable de Sitter vacua.
