The solitons solution of BKP equation can be constructed by the Pfaffian structure. Then one investigates the real line solitons structure of BKP equation using the totally non-negative Grassmannian. Especially, the N-soliton solution is studied and its self-dual Tau function is obtained. Also, one can construct the totally non-negative Grassmannian of the Sawada-Kotera equation for its real line solitons.


Keywords: Pfaffian, Grassmannian, Line solitons, Sawada-Kotera equation