The paper is devoted to introduce the notion of rough sets within the context of residuated lattices. By considering the notion of a residuated lattice, we
concern a relationship between rough sets theory and residuated lattices theory.
We shall introduce the notion of rough subalgebra (resp. filter)
with respect to a filter of a residuated lattice, which is an extended
notion of subalgebra (resp. filter) in a residuated lattice and investigate
some of their properties.