Article Outline
Glossary
Definition of the Subject
Introduction
Poincaré–Dulac Normal Forms
Convergence and Convergence Problems
Lie Algebra Arguments
NFIM and Sets of Analyticity
Hamiltonian Systems
Future Directions
Bibliography
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Abbreviations
- Resonant eigenvalues:
-
Let B be a linear endomorphism of \({\mathbb{C}^n}\), with eigenvalues \({\lambda_1,\dots, \lambda_n}\) (counted according to multiplicity). One calls these eigenvalues resonant if there are integers \({d_j\geq 0}\), \({\sum d_j\geq 2}\), and some \({k\in\{1,\dots,n\}}\) such that
$$ d_1\lambda_1+\dots+d_n\lambda_n-\lambda_k=0\:. $$If B is represented by a matrix in Jordan canonical then the associated vector monomial \({x_1^{d_1}\dots x_n^{d_n} e_k}\) will be called a resonant monomial . (Here \({e_1,\dots,e_n}\) denote the standard basis, and the x i are the corresponding coordinates.)
- Poincaré–Dulac normal form :
-
Let \({f=B+\dots}\) be a formal or analytic vector field about 0, and let \({B_\mathrm{s}}\) be the semisimple part of B. Then one says that f is in Poincaré–Dulac normal form (PDNF) if \({[B_\mathrm{s}, f]=0}\). An equivalent characterization, if B is in Jordan form, is to say that only resonant monomials occur in the series expansion.
- Normalizing transformations and convergence:
-
A relatively straightforward argument shows that any formal vector field \({f=B+\dots}\) can be transformed to a formal vector field in PDNF via a formal power series transformation. But for analytic vector fields, the existence of a convergent transformation is not assured. There are two obstacles to convergence: First, the possible existence of small denominators (roughly, this means that the eigenvalues satisfy “near‐resonance conditions”); and second, “algebraic” obstructions due to the particular form of the normalized vector field.
- Lie algebras of vector fields:
-
The vector space of analytic vector fields on an open subset U of \({{\mathbb C}^n}\), with the bracket \({[p, q]}\) defined by
$$ [p, q](x):=Dq(x)\,p(x) - Dp(x)\,q(x) $$becomes a Lie algebra , as is well known. Mutatis mutandis, this also holds for local analytic and for formal vector fields. As noted previously, PDNF is most naturally defined via this Lie bracket. Moreover, the “algebraic” obstructions to convergence are most appropriately discussed within the Lie algebra framework.
- Normal form on invariant manifolds:
-
While there may not exist a convergent transformation to PDNF for a given vector field f, one may have a convergent transformation to a “partially normalized” vector field, which admits a certain invariant manifold and is in PDNF when restricted to this manifold. This observation is of some practical importance.
Bibliography
Arnold VI (1982) Geometrical methods in the theory of ordinary differential equations. Springer, Berlin
Arnold VI, Kozlov VV, Neishtadt AI (1993) Mathematical aspects of classical and celestial mechanics. In: Arnold VI (ed) Dynamical Systems III, Encyclop Math Sci, vol 3, 2nd edn. Springer, New York
Bambusi D, Cicogna G, Gaeta G, Marmo G (1998) Normal forms, symmetry and linearization of dynamical systems. J Phys A 31:5065–5082
Bibikov YN (1979) Local theory of nonlinear analytic ordinary differential equations. Lecture Notes in Math 702. Springer, New York
Birkhoff GD (1927) Dynamical systems, vol IX. American Mathematical Society, Colloquium Publications, Providence, RI
Bruno AD (1971) Analytical form of differential equations. Trans Mosc Math Soc 25:131–288
Bruno AD (1989) Local methods in nonlinear differential equations. Springer, New York
Bruno AD, Edneral VF (2006) The normal form and the integrability of systems of ordinary differential equations. (Russian) Programmirovanie 3:22–29; translation in Program Comput Software 32(3):139–144
Bruno AD, Walcher S (1994) Symmetries and convergence of normalizing transformations. J Math Anal Appl 183:571–576
Chow S-N, Li C, Wang D (1994) Normal forms and bifurcations of planar vector fields. Cambridge Univ Press, Cambridge
Cicogna G (1996) On the convergence of normalizing transformations in the presence of symmetries. J Math Anal Appl 199:243–255
Cicogna G (1997) Convergent normal forms of symmetric dynamical systems. J Phys A 30:6021–6028
Cicogna G, Gaeta G (1999) Symmetry and perturbation theory. In: Nonlinear Dynamics, Lecture Notes in Phys 57. Springer, New York
Cicogna G, Walcher S (2002) Convergence of normal form transformations: The role of symmetries. Acta Appl Math 70:95–111
Cushman R, Sanders JA (1990) A survey of invariant theory applied to normal forms of vectorfields with nilpotent linear part, IMA vol Math Appl 19. Springer, New York, pp 82–106
DeLatte D, Gramchev T (2002) Biholomorphic maps with linear parts having Jordan blocks: linearization and resonance type phenomena. Math Phys Electron J 8(2):27 (electronic)
Dulac H (1912) Solutions d'un systéme d'équations différentielles dans le voisinage de valeurs singuliéres. Bull Soc Math Fr 40:324–383
Ecalle J (1981) Sur les fonctions résurgentes I. Publ Math d'Orsay 81(5):1–247
Ecalle J (1981) Sur les fonctions résurgentes II. Publ Math d'Orsay 81(6):248–531
Edneral VF (2005) Looking for periodic solutions of ODE systems by the normal form method. In: Differential equations with symbolic computation. Trends Math, Birkhäuser, Basel, pp 173–200
Gramchev T (2002) On the linearization of holomorphic vector fields in the Siegel domain with linear parts having nontrivial Jordan blocks SPT. In: Symmetry and perturbation theory (Cala Gonone). World Sci Publ, River Edge, NJ, pp 106–115
Gramchev T, Tolis E (2006) Solvability of systems of singular partial differential equations in function spaces. Integral Transforms Spec Funct 17:231–237
Gramchev T, Walcher S (2005) Normal forms of maps: Formal and algebraic aspects. Acta Appl Math 87(1–3):123–146
Gramchev T, Yoshino M (1999) Rapidly convergent iteration method for simultaneous normal forms of commuting maps. Math Z 231:745–770
Iooss G, Adelmeyer M (1992) Topics in Bifurcation Theory and Applications. World Scientific, Singapore
Ito H (1989) Convergence of Birkhoff normal forms for integrable systems. Comment Math Helv 64:412–461
Ito H (1992) Integrability of Hamiltonian systems and Birkhoff normal forms in the simple resonance case. Math Ann 292:411–444
Kappeler T, Kodama Y, Nemethi A (1998) On the Birkhoff normal form of a completely integrable system near a fixed point in resonance. Ann Scuola Norm Sup Pisa Cl Sci 26:623–661
Markhashov LM (1974) On the reduction of an analytic system of differential equations to the normal form by an analytic transformation. J Appl Math Mech 38:788–790
Martinet J, Ramis J-P (1983) Classification analytique des équations différentielles non linéaires résonnantes du premier ordre. Ann Sci Ecole Norm Sup 16:571–621
Perez Marco R (1995) Nonlinearizable holomorphic dynamics having an uncountable number of symmetries. Invent Math 119:67–127
Perez–Marco R (1997) Fixed points and circle maps. Acta Math 179:243–294
Perez–Marco R (2003) Convergence and generic divergence of the Birkhoff normal form. Ann Math 157:557–574
Pliss VA (1965) On the reduction of an analytic system of differential equations to linear form. Differ Equ 1:153–161
Poincaré H (1879) Sur les propriétés des fonctions deéfinies par les équations aux differences partielles. These, Paris
Sanders JA (2003) Normal form theory and spectral sequences. J Differential Equations 192:536–552
Sanders JA (2005) Normal form in filtered Lie algebra representations. Acta Appl Math 87:165–189
Siegel CL (1952) Über die Normalform analytischer Differentialgleichungen in der Nähe einer Gleichgewichtslösung. Nachr Akad Wiss Göttingen, Math-Phys Kl, pp 21–30
Stolovitch L (2000) Singular complete integrability. IHES Publ Math 91:133–210
Vey J (1979) Algébres commutatives de champs de vecteurs isochores. Bull Soc Math France 107(4):423–432
Verhulst F (2005) Methods and applications of singular perturbations Boundary layers and multiple timescale dynamics. In: Texts in Applied Mathematics, vol 50. Springer, New York
Voronin SM (1981) Analytic classification of germs of conformal mappings \({(\mathbb{C},0)\rightarrow(\mathbb{C},0)}\). Funct Anal Appl 15:1–13
Walcher S (1991) On differential equations in normal form. Math Ann 291:293–314
Walcher S (1993) On transformations into normal form. J Math Anal Appl 180(2):617–632
Walcher S (2000) On convergent normal form transformations in presence of symmetries. J Math Anal Appl 244:17–26
Zung NT (2002) Convergence versus integrability in Poincaré–Dulac normal form. Math Res Lett 9(2–3):217–228
Zung NT (2005) Convergence versus integrability in Birkhoff normal form. Ann Math (2) 161(1):141–156
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2012 Springer-Verlag
About this entry
Cite this entry
Walcher, S. (2012). Perturbative Expansions, Convergence of. In: Meyers, R. (eds) Mathematics of Complexity and Dynamical Systems. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-1806-1_87
Download citation
DOI: https://doi.org/10.1007/978-1-4614-1806-1_87
Publisher Name: Springer, New York, NY
Print ISBN: 978-1-4614-1805-4
Online ISBN: 978-1-4614-1806-1
eBook Packages: Mathematics and StatisticsReference Module Computer Science and Engineering