Abstract
The Butcher group is a powerful tool to analyse integration methods for ordinary differential equations, in particular Runge–Kutta methods. In the present paper, we complement the algebraic treatment of the Butcher group with a natural infinite-dimensional Lie group structure. This structure turns the Butcher group into a real analytic Baker–Campbell–Hausdorff Lie group modelled on a Fréchet space. In addition, the Butcher group is a regular Lie group in the sense of Milnor and contains the subgroup of symplectic tree maps as a closed Lie subgroup. Finally, we also compute the Lie algebra of the Butcher group and discuss its relation to the Lie algebra associated with the Butcher group by Connes and Kreimer.
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Notes
The same construction can be performed for tree maps with values in the field of complex numbers. The group \(G_{{\mathrm {TM}}}^{{\mathbb {C}}}\) of complex-valued tree maps obtained in this way will be an important tool in our investigation. In fact, \(G_{{\mathrm {TM}}}^{{\mathbb {C}}}\) is a complex Lie group and the complexification (as a Lie group) of the Butcher group.
The term “ordered” refers to that the subtree remembers from which part of the tree it was cut.
If E and F are Fréchet spaces, real analytic maps in the sense just defined coincide with maps which are continuous and can be locally developed into a power series. (see [15, Proposition 4.1])
i.e. every open set in the box topology can be written as a union of boxes. Note that we can not describe this topology via seminorms as it does not turn \({\mathbb {K}}^{{\mathcal {T}}_0}\) into a topological vector space.
While addition is continuous, scalar multiplication fails to be continuous, cf. the discussion of the problem in [18].
The natural choice for this space is a locally convex direct limit topology. Note that as \({\mathcal {T}}_0\) is countable, the box topology coincides with the inductive limit topology by [21, Proposition 4.1.4].
In [10], the authors work over the field \({\mathbb {Q}}\) of rational numbers. However, by applying \(\cdot \otimes _{{\mathbb {Q}}} {\mathbb {R}}\) to the \({\mathbb {Q}}\)-algebras, the same result holds for the field \({\mathbb {R}}\) (cf. [10, p. 41]). The thesis of Mencattini [26] contains an explicit computation for \({\mathbb {R}}\) and \({\mathbb {C}}\).
This follows from [17, Remark 2.12 and Lemma 2.5] for manifolds modelled on Fréchet spaces.
References
H. Alzaareer and A. Schmeding. Differentiable mappings on products with different degrees of differentiability in the two factors. Expositiones Mathematicae, (33):184–222, 2015. doi:10.1016/j.exmath.2014.07.002.
A. Bastiani. Applications différentiables et variétés différentiables de dimension infinie. J. Analyse Math., 13:1–114, 1964.
G. Bogfjellmo, R. Dahmen, and A. Schmeding. Character groups of Hopf algebras as infinite-dimensional Lie groups. arXiv:1501.05221v3, Apr. 2015.
C. Brouder. Trees, renormalization and differential equations. BIT Num. Anal., 44:425–438, 2004.
J. C. Butcher. An algebraic theory of integration methods. Math. Comp., 26:79–106, 1972.
M. P. Calvo, A. Murua, and J. M. Sanz-Serna. Modified equations for ODEs. In Chaotic numerics (Geelong, 1993), volume 172 of Contemp. Math., pages 63–74. Amer. Math. Soc., Providence, RI, 1994.
M. P. Calvo and J. M. Sanz-Serna. Canonical B-series. Numer. Math., 67(2):161–175, 1994.
P. Chartier, E. Hairer, and G. Vilmart. Algebraic Structures of B-series. Foundations of Computational Mathematics, 10(4):407–427, 2010.
P. Chartier, A. Murua, and J. M. Sanz-Serna. Higher-order averaging, formal series and numerical integration II: The quasi-periodic case. Found. Comput. Math., 12(4):471–508, 2012.
A. Connes and D. Kreimer. Hopf Algebras, Renormalization and Noncommutative Geometry. Commun.Math.Phys. 199 203–242, 1998.
R. Dahmen. Direct Limit Constructions in Infinite Dimensional Lie Theory. PhD thesis, University of Paderborn, 2011. urn:nbn:de:hbz:466:2-239.
K. Deimling. Ordinary Differential Equations in Banach Spaces. Number 596 in Lecture Notes in Mathematics. Springer Verlag, Heidelberg, 1977.
K. Ebrahimi-Fard, J. M. Gracia-Bondia, and F. Patras. A Lie theoretic approach to renormalization. Commun.Math.Phys. 276 519-549, 2007.
H. Glöckner. Lie group structures on quotient groups and universal complexifications for infinite-dimensional Lie groups. J. Funct. Anal., 194(2):347–409, 2002.
H. Glöckner. Instructive examples of smooth, complex differentiable and complex analytic mappings into locally convex spaces. J. Math. Kyoto Univ., 47(3):631–642, 2007.
H. Glöckner. Regularity properties of infinite-dimensional Lie groups, and semiregularity. arXiv:1208.0715v3, Jan. 2015.
H. Glöckner. Infinite-dimensional Lie groups without completeness restrictions. In A. Strasburger, J. Hilgert, K. Neeb, and W. Wojtyński, editors, Geometry and Analysis on Lie Groups, volume 55 of Banach Center Publication, pages 43–59. Warsaw, 2002.
G. G. Gould. Locally unbounded topological fields and box topologies on products of vector spaces. J. London Math. Soc., 36:273–281, 1961.
E. Hairer and C. Lubich. The life-span of backward error analysis for numerical integrators. Numerische Mathematik, 76(4):441–462, 1997.
E. Hairer, C. Lubich, and G. Wanner. Geometric Numerical Integration, volume 31 of Springer Series in Computational Mathematics. Springer Verlag, \(^2\)2006.
H. Jarchow. Locally Convex Spaces. Lecture Notes in Mathematics 417. Teubner, Stuttgart, 1981.
H. Keller. Differential Calculus in Locally Convex Spaces. Lecture Notes in Mathematics 417. Springer Verlag, Berlin, 1974.
C. J. Knight. Box topologies. Quart. J. Math. Oxford Ser. (2), 15:41–54, 1964.
A. Kriegl and P. W. Michor. The convenient setting of global analysis, volume 53 of Mathematical Surveys and Monographs. AMS, 1997.
R. I. McLachlan, K. Modin, H. Munthe-Kaas, and O. Verdier. B-series methods are exactly the local, affine equivariant methods. arXiv:1409.1019v3, Sept. 2014.
I. Mencattini. Structure of the insertion elimination Lie algebra in the ladder case. ProQuest LLC, Ann Arbor, MI, 2005. Thesis (Ph.D.)–Boston University.
P. Michor. Manifolds of Differentiable Mappings. Shiva Mathematics Series 3. Shiva Publishing Ltd., Orpington, 1980.
J. Milnor. Remarks on infinite-dimensional Lie groups. In B. DeWitt and R. Stora, editors, Relativity, Groups and Topology II, pages 1007–1057. North Holland, New York, 1983.
K. Neeb. Towards a Lie theory of locally convex groups. Japanese Journal of Mathematics, 1(2):291–468, 2006.
H. H. Schaefer. Topological vector spaces. Springer-Verlag, New York-Berlin, 1971. Third printing corrected, Graduate Texts in Mathematics, Vol. 3.
Acknowledgments
The research on this paper was partially supported by the projects Topology in Norway (Norwegian Research Council Project 213458) and Structure Preserving Integrators, Discrete Integrable Systems and Algebraic Combinatorics (Norwegian Research Council Project 231632). The second author would also like to thank Reiner Hermann for helpful discussions on Hopf algebras. Furthermore, we thank the anonymous referees for their insightful comments which led to substantial improvements of the paper.
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Communicated by Arieh Iserles.
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Bogfjellmo, G., Schmeding, A. The Lie Group Structure of the Butcher Group. Found Comput Math 17, 127–159 (2017). https://doi.org/10.1007/s10208-015-9285-5
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DOI: https://doi.org/10.1007/s10208-015-9285-5
Keywords
- Butcher group
- Infinite-dimensional Lie group
- Hopf algebra of rooted trees
- Regularity of Lie groups
- Symplectic methods