Darboux transformation and Crum’s formula for multi-component integrable equations

We present the Darboux transformation and the N-soliton solution for the multi-component integrable equations which are associated with the Hermitian symmetric spaces. Using the Darboux covariance, we derive new integrable equations as well as known ones including the multi-component extensions of the nonlinear Schrödinger, the modified KdV, the SIT and the sine-Gordon equations. We also derive a closed form of the N-soliton solution in terms of the generalized Crum’s formula. The projection property of the Darboux transformation is explained.