“…Also, in [13] asymptotic behavior for the case α = 1, β ∈ (0, 1) and σ = 0 was obtained. Note that it is assumed that either α = 1 or β = 1 in [9,10,13,17,20], and moreover spatial fractional derivative ∆ γ p and time fractional derivative D σ t p are not obtained in [9,10,17,20] and [13] respectively. Our result substantially improves these results because we only assume α ∈ (0, 2) and β ∈ (0, ∞) and we provide two sides estimates of both space and time fractional derivatives of arbitrary order.…”