Construction of Recursion Formulas for Lax Pairs of (2+1)-Dimensional Equation: Modified Generalized Dispersive Long Wave Equation

In this article, we study the Lax pairs of -dimensional equation: the modified generalized dispersive long wave (MGDLW) equation. Based on the well-known binary Darboux transformation, we dig out the recursion formulas of the first part of the Lax pairs. Then by further discussion and doing some revisional work, we make the recursion formulas fit for the second part of Lax pairs. At last, some solutions to the MGDLW equation are worked out by using the recursion formula.

An Invariance for （2＋1）-Extension of Burgers Equation and Formulae to Obtain Solutions of KP Equation

In this article, we study the (2+1)-extension of Burgers equation and the KPequation. At first, based on a known Baecklund transformation and corresponding Lax pair, aninvariance which depends on two arbitrary functions for (2+1)-extension of Burgers equation isworked out. Given a known solution and using the invariance, we can find solutions of the(2+1)-extension of Burgers equation repeatedly. Secondly, we put forward an invariance of Burgersequation which cannot be directly obtained by constraining the invariance of the (2+1)-extension ofBurgers equation. Furthermore, we reveal that the invariance for finding the solutions of Burgersequation can help us find the solutions of KP equation. At last, based on the invariance of Burgersequation, the corresponding recursion formulae for finding solutions of KP equation are digged out.As the application of our theory, some examples have been put forward in this article and somesolutions of the (2+1)-extension of Burgers equation, Burgers equation and KP equation are obtained.