“…Signorini problems come up in the modeling of many realistic science and engineering applications such as the shallow dam problem [1][2][3][4], the electropaint process [3][4][5][6][7], the unilateral contact problem [8,9], the free boundary problem [10,11], and so on. Besides, in the theory of variational inequalities [12,13], a broad class of problems arising in industry, social, economics, finance, pure and applied sciences give rise to Signorini problems.…”