本文对满足条件1-4（或4＇）的一类具重特征的双曲拟微分算子（1）进行初步的讨论。

In this paper we will study the pseudo-differential operators P which satisfy conditions 1-4(or 4'). They constitute a class of hyperbolic operators with multi-characteristics.

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基于双曲型线性偏微分算子理论，引入并研究了具有非零初始值的拟线性双曲型方程的定解问题。

Based on theory of hyperbolic linear partial differential operator, the initial value problem of a kind of quasi-linear hyperbolic equations with non-zero initial values was introduced and studied.

youdao

基于双曲型线性偏微分算子理论，引入并研究了具有非零初始值的拟线性双曲型方程的定解问题。

Based on theory of hyperbolic linear partial differential operator, the initial value problem of a kind of quasi-linear hyperbolic equations with non-zero initial values was introduced and studied.

youdao