“…Higher-dimensional NLEEs are scientifically interesting: For example, some (3+1)-dimensional KdV-type equations can describe the dust-ion-acoustic waves in cosmic nonmagnetised dusty plasmas such as those in the supernova shells and Saturn's F-ring [28], and some (3+1)-dimensional NLEEs, with certain parameters, can reduce to the (2+1)-dimensional and (1+1)-dimensional NLEEs [29][30][31][32][33][34][35] where u is an analytic function depending on the scaled spatial coordinates (x, y, z) and temporal coordinate t. By virtue of the exp-function method [10] and bilinear method via the logarithm transformation [36], the soliton solutions of (2) have been discussed [10,36]. In the fluid and plasma dynamics, special cases of (2) are seen as follows: (a) When y = z, u(x, y, t) = (η, t) = [x + χ(y), t] with as χ an analytic function of y, (2) degenerates into the KdV equation [37],…”