(R3) : The pdf f(x;θ) is twice differentiable as a function of θ.
(R4) : The integral ∫f(x;θ) can be differentiated twice under the integral sign as a function of θ.
(R5) : The pdf f(x;θ) is three times differentiable as a function of θ. Further, for all θ∈Ω, there exist a constant c and a function M(x) such that ∂θ3∂3logf(x;θ)≤M(x) with Eθ0[M(X)]<∞, for all θ0−c<θ<θ0+c and all x in the support of X.