González Vieli, Francisco Javier Spherical means and iterated Helmholtz operators. (Moyennes sphériques et opérateur de Helmholtz itéré.) (French) Zbl 0840.43002 Colloq. Math. 68, No. 2, 207-218 (1995). Extending well known results valid for harmonic functions or more generally solutions for the Helmholtz equation, \(\Delta f + cf = 0\), the author gives a mean value formula for solutions of the iterated Helmholtz equation \((\Delta + c)^kf = 0\). Reviewer: M.Milman (Boca Raton) Cited in 1 Document MSC: 43A07 Means on groups, semigroups, etc.; amenable groups 35J30 Higher-order elliptic equations 42B10 Fourier and Fourier-Stieltjes transforms and other transforms of Fourier type Keywords:harmonic functions; Helmholtz equation; mean value formula; iterated Helmholtz equation PDFBibTeX XMLCite \textit{F. J. González Vieli}, Colloq. Math. 68, No. 2, 207--218 (1995; Zbl 0840.43002) Full Text: DOI EuDML