<p>In this paper, we consider second-order degenerate parabolic equations with complex, measurable, and time-dependent coefficients. The degenerate ellipticity is dictated by a spatial <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(A_2\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>A</mi> <mn>2</mn> </msub> </math></EquationSource> </InlineEquation>-weight. We prove that having a generalized fundamental solution with upper Gaussian bounds is equivalent to Moser’s <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(L^2\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>L</mi> <mn>2</mn> </msup> </math></EquationSource> </InlineEquation>-<InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(L^\infty \)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>L</mi> <mi>∞</mi> </msup> </math></EquationSource> </InlineEquation> estimates for local weak solutions. In the special case of real coefficients, Moser’s <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(L^2\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>L</mi> <mn>2</mn> </msup> </math></EquationSource> </InlineEquation>-<InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(L^\infty \)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>L</mi> <mi>∞</mi> </msup> </math></EquationSource> </InlineEquation> estimates are known, which provide an easier proof of Gaussian upper bounds, and a known Harnack inequality is then used to derive Gaussian lower bounds.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Degenerate parabolic equations in divergence form: fundamental solution and Gaussian bounds

  • Khalid Baadi

摘要

In this paper, we consider second-order degenerate parabolic equations with complex, measurable, and time-dependent coefficients. The degenerate ellipticity is dictated by a spatial \(A_2\) A 2 -weight. We prove that having a generalized fundamental solution with upper Gaussian bounds is equivalent to Moser’s \(L^2\) L 2 - \(L^\infty \) L estimates for local weak solutions. In the special case of real coefficients, Moser’s \(L^2\) L 2 - \(L^\infty \) L estimates are known, which provide an easier proof of Gaussian upper bounds, and a known Harnack inequality is then used to derive Gaussian lower bounds.