Integration of negative-order modified Korteweg–de Vries equation with an integral source

In this paper, it is shown that the modified Korteweg–de Vries (mKdV) equation of negative order with an integral source can be integrated by the method of the inverse spectral problem. The main result of this work is the derivation of the evolution of the spectral data of the Dirac system with a periodic potential associated with the solution of the negative-order modified Korteweg–de Vries equation with an integral source. The obtained results allow us to apply the inverse problem method to solve the negative-order modified Korteweg–de Vries equation with an integral source.