REMARKS ON NONLINEAR UNIFORMLY PARABOLIC EQUATIONS
REMARKS ON NONLINEAR UNIFORMLY PARABOLIC EQUATIONS
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关于非线性一致抛物线方程的注解
DOI:
10.1512/iumj.1998.47.1561
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发表时间:
1998
影响因子:
1.1
通讯作者:
A. Swiech
中科院分区:
文献类型:
--
作者:
M. Crandall;K. Fok;M. Kocan;A. Swiech
This paper provides a number of working tools for the discussion of fully nonlinear parabolic equations. These include: a proof that the maximum principle which provides L 1 estimates of \strong" solutions of extremal equations by L n+1 norms of the forcing term over the \contact set" remains valid for viscosity solutions in an L n+1 sense, a gradient estimate in L p for p < (n + 1)(n + 2) for solutions of extremal equations with forcing terms in L n+1 , the use of this estimate in improving the range of p for which the maximum principle rst alluded to holds (obtaining some p < n+1-but without the contact set), a proof of the strong solvability of Dirichlet problems for extremal equations with forcing terms in L p for some p < n + 1, and the twice parabolic diierentiability a.e. of W 2;1;p functions for (n + 2)=2 < p. 0. Introduction. In this work we provide a number of tools for the discussion of nonlinear parabolic equations under appropriate structure conditions. In particular, we ll gaps in the current literature and thereby prove a full generalization of the \maximum principle" (see below) to viscosity solutions of certain extremal fully nonlinear equations with measurable forcing terms. While going about this task, we must resolve certain existence questions, and this is done as well. The results obtained are formulated in terms of standard extremal equations so that they apply to many other equations. In addition, some new proofs of known (to varying degrees) results are given. Let 0 < be constants and deene P ? (X) = ? trace(X +) + trace(X ?) for X 2 S(n), the set of real symmetric n n matrices. Here trace(X +) (respectively, trace(X ?)) is the sum of the positive eigenvalues of X (respectively, ?X). Let 0 be another constant. We discuss several results concerning solutions of the parabolic inequality