Irregular Hodge filtration on twisted de Rham cohomology

Abstract

We give a definition and study the basic properties of the irregular Hodge filtration on the exponentially twisted de Rham cohomology of a smooth quasi-projective complex variety.Comment: 34 pages. Paper shortened, in particular, sections 3 and 6 in previous version have been removed; a mistake in the proof in old section 5 correcte