In this paper, we introduce the notions of (∈,∈ ∨ q)-N -ideals and (γ, δ)-N -ideals of subtraction algebras, which are generalization of N -ideals. Some characterization for these generalized N -ideals are derived. Also, we introduce the notions of (∈,∈ ∨ q)-N -ideals and N -ideals with thresholds of subtraction algebras. The characterization of N -ideals with thresholds by their closed (f, t)-...