Convolution powers of complex functions on Z d
Convolution powers of complex functions on Z d
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Z d 上复函数的卷积幂
DOI:
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发表时间:
2015
期刊:
影响因子:
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通讯作者:
M. V. Fedoryuk
中科院分区:
文献类型:
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作者:
Evan Randles;L. Saloff‐Coste;V. Thomée;M. V. Fedoryuk
The study of convolution powers of a finitely supported probability distribution φ on the d-dimensional square lattice is central to random walk theory. For instance, the nth convolution power φ is the distribution of the nth step of the associated random walk and is described by the classical local limit theorem. Following previous work of P. Diaconis and the authors, we explore the more general setting in which φ takes on complex values. This exploration, originally motivated by the problem of Erastus L. De Forest in data smoothing, has found applications to the theory of stability of numerical difference schemes in partial differential equations. For a complex valued function φ on Z, we ask and address four basic and fundamental questions about the convolution powers φ which concern sup-norm estimates, generalized local limit theorems, pointwise estimates, and stability. This work extends one-dimensional results of I. J. Schoenberg, T. N. E. Greville, P. Diaconis and the second author and, in the context of stability theory, results by V. Thomée and M. V. Fedoryuk.