A new proof of Moser's parabolic harnack inequality using the old ideas of Nash
A new proof of Moser's parabolic harnack inequality using the old ideas of Nash
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DOI:
10.1007/bf00251802
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发表时间:
1986-12
影响因子:
2.5
通讯作者:
E. Fabes;E. Fabes;D. Stroock;D. Stroock
中科院分区:
文献类型:
--
作者:
E. Fabes;E. Fabes;D. Stroock;D. Stroock
In 1958 Nash published his fundamental work on the local Holder continuity of solutions of second order parabolic equations with non-smooth coefficients ([7]). The primary purpose of that work was to study the properties of the fundamental solution corresponding to the parabolic operator and to derive from these properties the regularity for a general solution. Though the work is often cited in the literature about weak solutions of elliptic and parabolic equations, one feels that Nash's ideas were never fully understood (and maybe still are not) and that because of this the more understandable and seemingly more fruitful ideas of DeGiorgi ([3]) and Moser ([5],[6]) were subsequently adopted.In the present article, we return to Nash's ideas. In particular, by modifying and persuing his arguments, we establish directly what we feel is the logical goal of this line of reasoning, namely: the estiamtes for the fundamental solution first proved by DG Aronson ([1]). From Aronson's estimates the parabolic Harnack inequality of Moser ([6]) and, consequently (as was shown by Moser [6, p. 108]), Nash's local H6lder continuity of weak solutions to parabolic equations follow. That is, our approach reverses the chronological order in* which these results were derived originally. To make the above statements mathematically precise we introduce the basic notations and definitions to be used throughout this work. We will be studying parabolic operators of the form