  M.S. Rao recently investigated some sorts of special filters in distributive
pseudocomplemented lattices. In our paper we extend this study to lattices
which need neither be distributive nor pseudocomplemented. For this sake we
define a certain modification of the notion of a pseudocomplement as the set of
all maximal elements belonging to the annihilator of the corresponding element.
We prove several basic properties of this notion and then define coherent,
closed and median filters as well as D-filters. In order to be able to obtain
valuable results we often must add some additional assumptions on the
underlying lattice, e.g. that this lattice is Stonean or D-Stonean. Our results
relate properties of lattices and of corresponding filters. We show how the
structure of a lattice influences the form of its filters and vice versa.
