A simple formula is proven for an upper bound for amplitudes of hyperelliptic (finite‐gap or N‐phase) solutions of the derivative nonlinear Schrödinger equation. The upper bound is sharp, viz, it is attained for some initial conditions. The method used to prove the upper bound is the same method, with necessary modifications, used to prove the corresponding bound for solutions of the focusing NLS equation (Wright OC, III. Sharp upper bound for amplitudes of hyperelliptic solutions of the focusing nonlinear Schrödinger equation. Nonlinearity. 2019;32:1929‐1966).

中文翻译：

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导数非线性Schrödinger方程的超椭圆解的最大振幅

一个简单的公式证明了导数非线性Schrödinger方程的超椭圆（有限间隙或N相）解的振幅上限。上限很尖锐，即在某些初始条件下可以达到。用于证明上限的方法与用于证明聚焦NLS方程解的相应方法的方法相同，并进行了必要的修改（Wright OC，III。聚焦非线性Schrödinger方程的超椭圆解的振幅的尖锐上限） 。非线性2019; 32：1929年至1966年）。