We
call “asymptotic mean” (at +∞) of a real-valued function the number, supposed to exist, ,
and highlight its role in the geometric theory of asymptotic expansions in the
real domain of type (*) where the comparison functions ,
forming an asymptotic scale at +∞, belong to one of the three classes having a definite “type of variation” at +∞, slow, regular
or rapid. For regularly varying comparison functions we can characterize
the existence of an asymptotic expansion (*) by the nice property that a
certain quantity F(t) has an asymptotic mean at +∞. This quantity is
defined via a linear differential operator in f and admits of a remarkable geometric interpretation as it
measures the ordinate of the point wherein that special curve ,
which has a contact of order n -
References
[1]
Granata, A. (2007) Polynomial Asymptotic Expansions in the Real Domain: The Geometric, the Factorizational, and the Stabilization Approaches. Analysis Mathematica, 33, 161-198. http://dx.doi.org/10.1007/s10476-007-0301-0
[2]
Granata, A. (2010) The Problem of Differentiating an Asymptotic Expansion in Real Powers. Part I: Unsatisfactory or Partial Results by Classical Approaches. Analysis Mathematica, 36, 85-112. http://dx.doi.org/10.1007/s10476-010-0201-6
[3]
Granata, A. (2010) The Problem of Differentiating an Asymptotic Expansion in Real Powers. Part II: Factorizational Theory. Analysis Mathematica, 36, 173-218. http://dx.doi.org/10.1007/s10476-010-0301-3
[4]
Granata, A. (2011) Analytic Theory of Finite Asymptotic Expansions in the Real Domain. Part I: Two-Term Expansions of Differentiable Functions. Analysis Mathematica, 37, 245-287. (For an Enlarged Version with Corrected Misprints see: arxiv.org/abs/1405.6745v1 [mathCA]. http://dx.doi.org/10.1007/s10476-011-0402-7
[5]
Granata, A. (2014) Analytic Theory of Finite Asymptotic Expansions in the Real Domain. Part II: The Factorizational Theory for Chebyshev Asymptotic Scales. Electronically Archived—arXiv: 1406.4321v2 [math.CA].
[6]
Granata, A. (2015) The Factorizational Theory of Finite Asymptotic Expansions in the Real Domain: A Survey of the Main Results. Advances in Pure Mathematics, 5, 1-20. http://dx.doi.org/10.4236/apm.2015.51001
[7]
Haupt, O. (1922) über Asymptoten ebener Kurven. Journal für die Reine und Angewandte Mathematik, 152, 6-10; ibidem, 239.
[8]
Sanders, J.A. and Verhulst, F. (1985) Averaging Methods in Nonlinear Dynamical Systems. Springer-Verlag, New York.
[9]
Corduneanu, C. (1968) Almost Periodic Functions. Interscience Publishers, New York.
[10]
Faedo, S. (1946) Il Teorema di Fuchs per le Equazioni Differenziali Lineari a Coefficienti non Analitici e Proprietà Asintotiche delle Soluzioni. Annali di Matematica Pura ed Applicata (the 4th Series), 25, 111-133. http://dx.doi.org/10.1007/BF02418080
[11]
Hallam, T.G. (1967) Asymptotic Behavior of the Solutions of a Nonhomogeneous Singular Equation. Journal of Differential Equations, 3, 135-152. http://dx.doi.org/10.1016/0022-0396(67)90011-3
[12]
Hukuhara, M. (1934) Sur les Points Singuliers des équations Différentielles Linéaires; Domaine Réel. Journal of the Faculty of Science, Hokkaido University, Ser. I, 2, 13-88.
[13]
Ostrowski, A.M. (1951) Note on an Infinite Integral. Duke Mathematical Journal, 18, 355-359. http://dx.doi.org/10.1215/S0012-7094-51-01826-1
[14]
Agnew, R.P. (1942) Limits of Integrals. Duke Mathematical Journal, 9, 10-19. http://dx.doi.org/10.1215/S0012-7094-42-00902-5
[15]
Hardy, G.H. (1911) Fourier’s Double Integral and the Theory of Divergent Integrals. Transactions of the Cambridge Philosophical Society, 21, 427-451.
[16]
Hardy, G.H. (1949) Divergent Series. Oxford University Press, Oxford. (Reprinted in 1973)
[17]
Blinov, I.N. (1983) Absence of Exact Mean Values for Certain Bounded Functions. Izvestija Akademii Nauk SSSR. Serija Mathematicheskaja (Moscow), 47, 1162-1181.
[18]
Ditkine, V. and Proudnikov, A. (1979) Calcul Opérationnel. éditions Mir, Moscou.
[19]
Baumgartel, H. and Wollenberg, M. (1983) Mathematical Scattering Theory. Birkhauser Verlag, Berlin.
Bingham, N.H., Goldie, C.M. and Teugels, J.L. (1987) Regular Variation. Cambridge University Press, Cambridge. http://dx.doi.org/10.1017/CBO9780511721434
[22]
Hartman, Ph. (1952) On Non-Oscillatory Linear Differential Equations of Second Order. American Journal of Mathematics, 74, 389-400. http://dx.doi.org/10.2307/2372004