arXivDaily arXiv每日学术速递 周一至周五更新
arXiv math/0304335math.AP
收藏

解伪微分方程

Solving pseudo-differential equations

Nicolas Lerner

摘要:

1957年,Hans Lewy构造了一个反例,证明了非常简单和自然的微分方程可能没有局部解。1960年,L.Hörmander给出了这个反例的几何解释和推广。七十年代初,L.Nirenberg和F.Treves提出了一个关于主象征的几何条件,即所谓的条件$(ψ)$,并提供了强有力的论据,表明它应该等价于局部可解性。伪微分方程的可解性条件$(ψ)$的必要性由L.Hörmander在1981年证明。1994年,N.L.该条件$(ψ)$并不意味着伪微分方程在损失一个导数的情况下的可解性,这与几个作者的重复声明相矛盾。然而在1996年,N.Dencker证明了这些反例确实是可解的,但损失了两个导数。我们将从两个方面探讨这一现象的结构:一方面,存在满足条件$(ψ)$的一阶伪微分方程,使得在$L^2_{\text{loc}}$中的某个源不能找到$L^2_{\text{loc}}$解。另一方面,我们将看到,对于这些例子,在索伯列夫空间$H^{-1}_{\text{loc}}$中存在一个解。

英文摘要:

In 1957, Hans Lewy constructed a counterexample showing that very simple and natural differential equations can fail to have local solutions. A geometric interpretation and a generalization of this counterexample were given in 1960 by L.Hörmander. In the early seventies, L.Nirenberg and F.Treves proposed a geometric condition on the principal symbol, the so-called condition $(ψ)$, and provided strong arguments suggesting that it should be equivalent to local solvability. The necessity of condition $(ψ)$ for solvability of pseudo-differential equations was proved by L.Hörmander in 1981. In 1994, it was proved by N.L. that condition $(ψ)$ does not imply solvability with loss of one derivative for pseudo-differential equations, contradicting repeated claims by several authors. However in 1996, N.Dencker proved that these counterexamples were indeed solvable, but with a loss of two derivatives. We shall explore the structure of this phenomenon from both sides: on the one hand, there are first-order pseudo-differential equations satisfying condition $(ψ)$ such that no $L^2_{\text{loc}}$ solution can be found with some source in $L^2_{\text{loc}}$. On the other hand, we shall see that, for these examples, there exists a solution in the Sobolev space $H^{-1}_{\text{loc}}$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑