On the interplay between the Frobenius functor and its dual

Abstract

For a commutative Noetherian ring $R$ of prime characteristic, denote by ${}^{f}R$ the ring $R$ with the left structure given by the Frobenius map. We develop Thomas Marley's work on the property of the Frobenius functor $\F(-) = - \otimes_R {^f}R$ and show the interplay between $\F$ and its dual $\widetilde{\F}(-) = \Hom_R({}^{f}R, -)$ which is introduced by Jürgen Herzog.

11 pages; final version, to appear in Journal Algebra and its Application