Almost convergence and Euler totient matrix

This paper is devoted to study the almost convergent sequence space c(F) derived by the Euler totient matrix. It is proved that the space c(F) and the space of all almost convergent sequences are linearly isomorphic. Further, the ss-dual of the space c(F) is determined and Euler totient core of a complex-valued sequence has been defined. Finally, inclusion theorems related to this new type of core are obtained.