Poisson Kernel
The integral kernel in the Poisson integral, given by
for the open unit disk D(0,1). Writing z_0=re^(itheta) and taking D(0,R) gives
K(r,theta) = [画像:1/(2pi)R[(R+re^(itheta))/(R-re^(itheta))]]
(2)
(Krantz 1999, p. 93).
In three dimensions,
where a=|y| and
The Poisson kernel for the n-ball is
where D_(n) is the outward normal derivative at point z on a unit n-sphere and
Let u be harmonic on a neighborhood of the closed unit disk D^_(0,1), then the reproducing property of the Poisson kernel states that for z in D(0,1),
(Krantz 1999, p. 94).
See also
Dirichlet Problem, Harmonic Function, Mean-Value Property, Poisson IntegralExplore with Wolfram|Alpha
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References
Gradshteyn, I. S. and Ryzhik, I. M. Tables of Integrals, Series, and Products, 6th ed. San Diego, CA: Academic Press, p. 1090, 2000.Krantz, S. G. "The Poisson Kernel." §7.3.2 in Handbook of Complex Variables. Boston, MA: Birkhäuser, p. 93, 1999.Referenced on Wolfram|Alpha
Poisson KernelCite this as:
Weisstein, Eric W. "Poisson Kernel." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/PoissonKernel.html