“…Nonlinear and dispersive long gravity waves traveling along two horizontal directions in the shallow water of uniform depth have been said to be governed by a (2 + 1)-dimensional BKK system as follows (Ying and Lou, 2001; Ruan and Chen, 1998; Tang et al , 2020; Rizvi et al , 2020; Wen, 2011; Kassem and Rashed, 2019; Yamgoué et al , 2019; Jiang et al , 2017; Lan et al , 2017): where u = u ( x , y , t ) denotes the height of the water surface above a horizontal bottom, v = v ( x , y , t ) is the horizontal velocity of the water wave, and the subscripts represent the partial derivatives with respect to the scaled space variables x , y and time variable t . When y = x , System (1) has been reduced to a (1 + 1)-dimensional BKK system, which is used to describe the propagation of the long waves in shallow water (Ying and Lou, 2001).…”