Abstract

We define a σ-ideal J D on the set of functions ω ω with the property that a real x ∈ ω ω is a Hechler real over V if and only if x omits all Borel sets in J D . In fact we define a topology D on ω ω related to Hechler forcing such that J D is the family of first category sets in D. We study cardinal invariants of the ideal J D