Let D(A) be the domain of an m-accretive operator A on a Banach space E. We provide sufficient conditions for the closure of D(A) to be convex and for D(A) to coincide with E itself. Several related results and pertinent examples are also included.Proof. Let x, y ∈ D(A), x = y, and t ∈ (0, 1) be given. Consider z := tx + (1 − t)y. We first prove that lim λ→0 + J λ (z) = z, and then it follows that z ∈ D(A), as required.To this end, fix u ∈ A(x), v ∈ A(y) and set u λ = x + λu, v λ = y + λv. It is clear thatand, consequently,Analogously, one can also check that J λ (z) − y z − y + λ v . Since E is reflexive, there exists a sequence (λ n ) such that λ n → 0 + and J λn z w ∈ X. By the weak lower semicontinuity of the norm, we have