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Asymptotic Expansions of the Heat Kernel of the Laplacian for General Annular Bounded Domains with Robin Boundary Conditions:Further Results
作者姓名:E.M.E.ZAYED
作者单位:DepartmentofMathematics,FacultyofScience,ZagazigUniversity,Zagazig,Egypt
摘    要:The asymptotic expansions of the trace of the heat kernel θ(t)=∑^∞v=1^exp(-tλv) for small positive t,where {λv} are the eigenvalues of the negative Laplacian -△n=-∑^ni=1(D/Dx^1)^2 in R^2(n=2 or 3),are studied for a general annular bounded domain Ω with a smooth inner boundary DΩ1 and a smooth outer boundary DΩ2,where a finite number of piecewise smooth Robin boundary conditions(D/Dnj γh)Ф=0 on the components Гj(j= 1,...,m) of (DΩ1 and on the components Гj (j=k 1,…,m) of of DΩ2 are considered such that DΩl=U^kj=lГj and DΩ2= U^m=k 1Гj and where the coefficients γj(j=1,...,m) are piecewise smooth positive functions. Some applications of θ(t) for an ideal gas enclosed in the general annular bounded domain Ω are given. Further results are also obtained.

关 键 词:渐近展开公式  罗宾边界  环形域  拉普拉斯算子
收稿时间:13 August 2001

Asymptotic Expansions of the Heat Kernel of the Laplacian for General Annular Bounded Domains with Robin Boundary Conditions: Further Results
E.M.E.ZAYED.Asymptotic Expansions of the Heat Kernel of the Laplacian for General Annular Bounded Domains with Robin Boundary Conditions: Further Results[J].Acta Mathematica Sinica,2003,19(4):679-694.
Authors:Email author" target="_blank">E?M?E?ZayedEmail author
Institution:(1) Department of Mathematics, Faculty of Science, Zagazig University, Zagazig, Egypt
Abstract:Abstract The asymptotic expansions of the trace of the heat kernel $$
\Theta {\left( t \right)} = {\sum\nolimits_{v - 1}^\infty  {{\kern 1pt} {\kern 1pt} \exp {\left( { - t\lambda _{v} } \right)}} }
$$ for small positive t, where {λ v } are the eigenvalues of the negative Laplacian $$
 - \Delta _{n}  =  - {\sum\nolimits_{i = 1}^n {{\left( {\frac{\partial }
{{\partial x^{i} }}} \right)}^{2} } }
$$ in R n (n = 2 or 3), are studied for a general annular bounded domain Ω with a smooth inner boundary $$
\partial \Omega _{1} 
$$ and a smooth outer boundary $$
\partial \Omega _{2} 
$$ , where a finite number of piecewise smooth Robin boundary conditions $$
{\left( {\frac{\partial }
{{\partial n_{j} }} + \gamma _{j} } \right)}\phi  = 0
$$ on the components Γ j (j = 1, ..., k) of $$
\partial \Omega _{1} 
$$ and on the components Γ j (j = k+1, ...,m) of $$
\partial \Omega _{2} 
$$ are considered such that $$
\partial \Omega _{1}  =  \cup ^{k}_{{j = 1}} \Gamma _{j} 
$$ and $$
\partial \Omega _{2}  =  \cup ^{m}_{{j = k + 1}} \Gamma _{j} 
$$ and where the coeffcients γ j (j = 1, ...,m) are piecewise smooth positive functions. Some applications of Θ(t) for an ideal gas enclosed in the general annular bounded domain Ω are given. Further results are also obtained.
Keywords:Inverse problem  Heat kernel  Eigenvalues  Robin boundary conditions  Classical ideal gas
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