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On the Dimension of Certain Graded Lie Algebras Arising in Geometric Integration of Differential Equations

Published online by Cambridge University Press:  01 February 2010

Arieh Iserles
Affiliation:
Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW, [email protected]
Antonella Zanna
Affiliation:
Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW, [email protected]

Abstract

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Many discretization methods for differential equations that evolve in Lie groups and homogeneous spaces advance the solution in the underlying Lie algebra. The main expense of computation is the calculation of commutators, a task that can be made significantly cheaper by the introduction of appropriate bases of function values and by the exploitation of redundancies inherent in a Lie-algebraic structure by means of graded spaces. In many Lie groups of practical interest a convenient alternative to the exponential map is a Cayley transformation, and the subject of this paper is the investigation of graded algebras that occur in this context. To this end we introduce a new concept, a hierarchical algebra, a Lie algebra equipped with a countable number of m-nary multilinear operations which display alternating symmetry and a ‘hierarchy condition’. We present explicit formulae for the dimension of graded subspaces of free hierarchical algebras and an algorithm for the construction of their basis. The paper is concluded by reviewing a number of applications of our results to numerical methods in a Lie-algebraic setting.

Type
Research Article
Copyright
Copyright © London Mathematical Society 2000

References

1. Budd, C. J. and Iserles, A., ‘Geometric integration: numerical solution of differential equations on manifolds’, Philos. Trans. Roy. Soc. London Ser. A 357 (1999) 945956.CrossRefGoogle Scholar
2. Celledont, E. and Iserles, A., ‘Methods for the approximation of the matrix exponential in a Lie-algebraic setting’, Tech. Rep. 015, Mathematical Sciences Research Institute, Berkeley, California, 1999; IMA J. Numer. Anal., to appear.Google Scholar
3. Cools, R., ‘Constructing cubature formulae: the science behind the art’, Acta Numerica 6 (1997) 154.CrossRefGoogle Scholar
4. Crouch, P. and Grossman, R., ‘Numerical integration of ordinary differential equations on manifolds’, J. Nonlinear Sci. 3 (1993) 133.CrossRefGoogle Scholar
5. Dieci, L., Russell, R. D. and Van Vleck, E. S., ‘Unitary integrators and applications to continuous orthonormalization techniques’, SI AM J. Numer. Anal. 31 (1994) 261281.CrossRefGoogle Scholar
6. Diele, F., Lopez, L. and Peluso, R., ‘The Cayley transform in the numerical solution of unitary differential systems’, Adv. Comput. Math. 8 (1998) 317334.CrossRefGoogle Scholar
7. Engø, K., ‘On the construction of geometric integrators in the RKMK class‘, Tech. Rep. No. 158, Department of Informatics, University of Bergen, Norway, 1998.Google Scholar
8. Fer, F., ‘Résolution del l'equation matricielle par produit infini d'exponentielles matricielles’, Acad. Roy. Belg. Bull. Cl. Sci. AA (1958) 818829.Google Scholar
9. Iserles, A., ‘Solving linear ordinary differential equations by exponentials of iterated commutators’, burner. Math. 45 (1984) 183199.Google Scholar
10. Iserles, A., A first course in the numerical analysis of differential equations (Cam bridge University Press, Cambridge, 1996).Google Scholar
11. Iserles, A., ‘On Cayley-transform methods for the discretization of Lie-group equations’, Tech. Rep. NA1999/4, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, 1999.Google Scholar
12. Iserles, A. and Nørsett, S. P., ‘On the solution of linear differential equations in Lie groups’, Philos. Trans. Roy. Soc. London Sen A 357 (1999) 9831019.CrossRefGoogle Scholar
13. Lewis, D. and Simo, J. C., ‘Conserving algorithms for the dynamics of Hamiltonian systems on Lie groups’, J. Nonlinear Sci. 4 (1994) 253299.CrossRefGoogle Scholar
14. Magnus, W., ‘On the exponential solution of differential equations for a linear operator’, Comm. Pure Appl. Maths VII (1954) 649673.CrossRefGoogle Scholar
15. McLachlan, R. I., Quispel, G. R. W. and Robidoux, N., ‘Geometric integration using discrete gradients’, Philos. Trans. Roy. Soc. London Ser. A 357 (1999) 10211045.CrossRefGoogle Scholar
16. Munthe-Kaas, H., ‘Runge-Kutta methods on Lie groups’, BIT 38 (1998) 92111.CrossRefGoogle Scholar
17. Munthe-Kaas, H. and Owren, B., ‘Computations in a free Lie algebra’, Philos. Trans. Roy. Soc. London Ser A 357 (1999) 957981.CrossRefGoogle Scholar
18. Munthe-Kaas, H. and Zanna, A., ‘Numerical integration of differential equations on homogeneous manifolds’, Foundations of computational mathematics (ed. Cucker, F. and Shub, M., Springer Verlag, 1997) 305315.CrossRefGoogle Scholar
19. Onischik, A. L. (ed.), Lie groups and Lie algebras, Encyclopaedia Math. Sci. 20 (Springer-Verlag, Berlin, 1993).CrossRefGoogle Scholar
20. Owren, B. and Marthinsen, A., ‘Integration methods based on canonical coordinates of the second kind’, Tech. Rep. Numerics No. 5/1999, Norwegian University of Science and Technology, Trondheim, Norway, 1999.Google Scholar
21. Zanna, A., ‘Collocation and relaxed collocation for the Fer and the Magnus expansions’, Tech. Rep. NA1997/17, Department of Applied Mathematics and Theoretical Physics, University of Cambridge, 1997; SIAM J. Num. Anal., to appear.Google Scholar