Abstract: This paper describes an exact limit procedure by which a simple formula for the N-doublepole solution to the modified KdV equation is derived from its 2N-soliton solution in the Hirota’s form. This procedure is general and can be applied to other nonlinear evolution equations with multi-soliton solutions in the Hirota's form.
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Key words: 2N-soliton solution, bilinear equation, limit procedure, N-doublepole solution, modified KdV equation