# American Institute of Mathematical Sciences

December  2019, 6(2): 345-360. doi: 10.3934/jcd.2019017

## The Lie algebra of classical mechanics

 1 School of Fundamental Sciences, Massey University, Palmerston North, New Zealand 2 Department of Computer Science and Artificial Intelligence, University of the Basque Country (UPV/EHU), Lardizabal 1 20018 Donostia / San Sebastian, Spain

Received  May 2019 Revised  September 2019 Published  November 2019

Classical mechanical systems are defined by their kinetic and potential energies. They generate a Lie algebra under the canonical Poisson bracket. This Lie algebra, which is usually infinite dimensional, is useful in analyzing the system, as well as in geometric numerical integration. But because the kinetic energy is quadratic in the momenta, the Lie algebra obeys identities beyond those implied by skew symmetry and the Jacobi identity. Some Poisson brackets, or combinations of brackets, are zero for all choices of kinetic and potential energy, regardless of the dimension of the system. Therefore, we study the universal object in this setting, the 'Lie algebra of classical mechanics' modelled on the Lie algebra generated by kinetic and potential energy of a simple mechanical system with respect to the canonical Poisson bracket. We show that it is the direct sum of an abelian algebra $\mathfrak{X}$, spanned by 'modified' potential energies and isomorphic to the free commutative nonassociative algebra with one generator, and an algebra freely generated by the kinetic energy and its Poisson bracket with $\mathfrak{X}$. We calculate the dimensions $c_n$ of its homogeneous subspaces and determine the value of its entropy $\lim_{n\to\infty} c_n^{1/n}$. It is $1.8249\dots$, a fundamental constant associated to classical mechanics. We conjecture that the class of systems with Euclidean kinetic energy metrics is already free, i.e., that the only linear identities satisfied by the Lie brackets of all such systems are those satisfied by the Lie algebra of classical mechanics.

Citation: Robert I. McLachlan, Ander Murua. The Lie algebra of classical mechanics. Journal of Computational Dynamics, 2019, 6 (2) : 345-360. doi: 10.3934/jcd.2019017
##### References:
 [1] N. Bergeron and J. L. Loday, The symmetric operation in a free pre-Lie algebra is magmatic, Proc. Amer. Math. Soc., 139 (2011), 1585-1597.  doi: 10.1090/S0002-9939-2010-10813-4.  Google Scholar [2] S. Blanes, F. Casas and J. Ros, Processing symplectic methods for near-integrable Hamiltonian systems, Celest. Mech. Dyn. Astr., 77 (2000), 17-35.  doi: 10.1023/A:1008311025472.  Google Scholar [3] S. Blanes, F. Casas and J. Ros, High-order Runge-Kutta-Nystrom geometric methods with processing, Appl. Numer. Math., 39 (2001), 245-259.  doi: 10.1016/S0168-9274(00)00035-0.  Google Scholar [4] S. Blanes and P. C. Moan, Practical symplectic partitioned Runge-Kutta and Runge-Kutta-Nyström methods, J. Comput. Appl. Math., 142 (2002), 313-330.  doi: 10.1016/S0377-0427(01)00492-7.  Google Scholar [5] M. P. Calvo Cabrero, Métodos Runge-Kutta-Nyström Simplécticos, Tesis Doctoral, Universidad de Valladolid, 1992. Google Scholar [6] F. Chapoton and M. Livernet, Pre-Lie algebras and the rooted trees operad, International Math. Research Notices, 8 (2001), 395-408.  doi: 10.1155/S1073792801000198.  Google Scholar [7] M. Grayson and R. Grossman, Models for nilpotent free Lie algebras, J. Algebra, 135 (1990), 177-191.  doi: 10.1016/0021-8693(90)90156-I.  Google Scholar [8] E. Hairer, C. Lubich and G. Wanner, Geometric Numerical Integration: Structure-Preserving Algorithms for Ordinary Differential Equations, Springer Series in Computational Mathematics, 31. Springer-Verlag, Berlin, 2002. doi: 10.1007/978-3-662-05018-7.  Google Scholar [9] S.-J. Kang and M.-H. Kim, Free Lie algebras, generalized Witt formula, and the denominator identity, J. Algebra, 183 (1996), 560-594.  doi: 10.1006/jabr.1996.0233.  Google Scholar [10] M. Lazard, Groupes, Anneaux de Lie et problème de Burnside, Groups, Lie rings and cohomology theory, C.I.M.E. Summer Sch., Springer, Heidelberg, 20 (2011), 123-184.  doi: 10.1007/978-3-642-10937-9_2.  Google Scholar [11] M. Markl and E. Remm, Algebras with one operation including Poisson and other Lie-admissible algebras, J. Algebra, 299 (2006), 171-189.  doi: 10.1016/j.jalgebra.2005.09.018.  Google Scholar [12] R. I. McLachlan, On the numerical integration of ordinary differential equations by symmetric composition methods, SIAM J. Sci. Comput., 16 (1995), 151-168.  doi: 10.1137/0916010.  Google Scholar [13] R. I. McLachlan and G. R. W. Quispel, Splitting methods, Acta Numer., 11 (2002), 341-434.  doi: 10.1017/S0962492902000053.  Google Scholar [14] R. I. McLachlan and B. Ryland, The algebraic entropy of classical mechanics, J. Math. Phys., 44 (2003), 3071-3087.  doi: 10.1063/1.1576904.  Google Scholar [15] H. Munthe-Kaas and B. Owren, Computations in a free Lie algebra, R. Soc. Lond. Philos. Trans. A Math. Phys. Eng. Sci., 357 (1999), 957-981.  doi: 10.1098/rsta.1999.0361.  Google Scholar [16] A. Murua, Formal series and numerical integrators, Part I: Systems of ODEs and symplectic integrators, Appl. Numer. Math., 29 (1999), 221-251.  doi: 10.1016/S0168-9274(98)00064-6.  Google Scholar [17] R. Otter, The number of trees, Ann. Math., 49 (1948), 583-599.  doi: 10.2307/1969046.  Google Scholar [18] C. Reutenauer, Free Lie Algebras, London Mathematical Society Monographs. New Series, 7. Oxford Science Publications. The Clarendon Press, Oxford University Press, New York, 1993.  Google Scholar [19] N. J. A. Sloane, The on-line encyclopedia of integer sequences, Notices Amer. Math. Soc., 50 (2003), 912–915, https://oeis.org.  Google Scholar [20] J. H. M. Wedderburn, The functional equation $g(x^2) = 2\alpha x + [g(x)]^2$, Ann. Math., 24 (1922), 121-140.  doi: 10.2307/1967710.  Google Scholar [21] J. Wisdom, M. Holman and J. Touma, Symplectic correctors, Integration Algorithms and Classical Mechanics, Fields Inst. Commun., Amer. Math. Soc., Providence, RI, 10 (1996), 217-244.   Google Scholar [22] H. Yoshida, Construction of higher order symplectic integrators, Phys. Lett. A, 150 (1990), 262-268.  doi: 10.1016/0375-9601(90)90092-3.  Google Scholar

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##### References:
 [1] N. Bergeron and J. L. Loday, The symmetric operation in a free pre-Lie algebra is magmatic, Proc. Amer. Math. Soc., 139 (2011), 1585-1597.  doi: 10.1090/S0002-9939-2010-10813-4.  Google Scholar [2] S. Blanes, F. Casas and J. Ros, Processing symplectic methods for near-integrable Hamiltonian systems, Celest. Mech. Dyn. Astr., 77 (2000), 17-35.  doi: 10.1023/A:1008311025472.  Google Scholar [3] S. Blanes, F. Casas and J. Ros, High-order Runge-Kutta-Nystrom geometric methods with processing, Appl. Numer. Math., 39 (2001), 245-259.  doi: 10.1016/S0168-9274(00)00035-0.  Google Scholar [4] S. Blanes and P. C. Moan, Practical symplectic partitioned Runge-Kutta and Runge-Kutta-Nyström methods, J. Comput. Appl. Math., 142 (2002), 313-330.  doi: 10.1016/S0377-0427(01)00492-7.  Google Scholar [5] M. P. Calvo Cabrero, Métodos Runge-Kutta-Nyström Simplécticos, Tesis Doctoral, Universidad de Valladolid, 1992. Google Scholar [6] F. Chapoton and M. Livernet, Pre-Lie algebras and the rooted trees operad, International Math. Research Notices, 8 (2001), 395-408.  doi: 10.1155/S1073792801000198.  Google Scholar [7] M. Grayson and R. Grossman, Models for nilpotent free Lie algebras, J. Algebra, 135 (1990), 177-191.  doi: 10.1016/0021-8693(90)90156-I.  Google Scholar [8] E. Hairer, C. Lubich and G. Wanner, Geometric Numerical Integration: Structure-Preserving Algorithms for Ordinary Differential Equations, Springer Series in Computational Mathematics, 31. Springer-Verlag, Berlin, 2002. doi: 10.1007/978-3-662-05018-7.  Google Scholar [9] S.-J. Kang and M.-H. Kim, Free Lie algebras, generalized Witt formula, and the denominator identity, J. Algebra, 183 (1996), 560-594.  doi: 10.1006/jabr.1996.0233.  Google Scholar [10] M. Lazard, Groupes, Anneaux de Lie et problème de Burnside, Groups, Lie rings and cohomology theory, C.I.M.E. Summer Sch., Springer, Heidelberg, 20 (2011), 123-184.  doi: 10.1007/978-3-642-10937-9_2.  Google Scholar [11] M. Markl and E. Remm, Algebras with one operation including Poisson and other Lie-admissible algebras, J. Algebra, 299 (2006), 171-189.  doi: 10.1016/j.jalgebra.2005.09.018.  Google Scholar [12] R. I. McLachlan, On the numerical integration of ordinary differential equations by symmetric composition methods, SIAM J. Sci. Comput., 16 (1995), 151-168.  doi: 10.1137/0916010.  Google Scholar [13] R. I. McLachlan and G. R. W. Quispel, Splitting methods, Acta Numer., 11 (2002), 341-434.  doi: 10.1017/S0962492902000053.  Google Scholar [14] R. I. McLachlan and B. Ryland, The algebraic entropy of classical mechanics, J. Math. Phys., 44 (2003), 3071-3087.  doi: 10.1063/1.1576904.  Google Scholar [15] H. Munthe-Kaas and B. Owren, Computations in a free Lie algebra, R. Soc. Lond. Philos. Trans. A Math. Phys. Eng. Sci., 357 (1999), 957-981.  doi: 10.1098/rsta.1999.0361.  Google Scholar [16] A. Murua, Formal series and numerical integrators, Part I: Systems of ODEs and symplectic integrators, Appl. Numer. Math., 29 (1999), 221-251.  doi: 10.1016/S0168-9274(98)00064-6.  Google Scholar [17] R. Otter, The number of trees, Ann. Math., 49 (1948), 583-599.  doi: 10.2307/1969046.  Google Scholar [18] C. Reutenauer, Free Lie Algebras, London Mathematical Society Monographs. New Series, 7. Oxford Science Publications. The Clarendon Press, Oxford University Press, New York, 1993.  Google Scholar [19] N. J. A. Sloane, The on-line encyclopedia of integer sequences, Notices Amer. Math. Soc., 50 (2003), 912–915, https://oeis.org.  Google Scholar [20] J. H. M. Wedderburn, The functional equation $g(x^2) = 2\alpha x + [g(x)]^2$, Ann. Math., 24 (1922), 121-140.  doi: 10.2307/1967710.  Google Scholar [21] J. Wisdom, M. Holman and J. Touma, Symplectic correctors, Integration Algorithms and Classical Mechanics, Fields Inst. Commun., Amer. Math. Soc., Providence, RI, 10 (1996), 217-244.   Google Scholar [22] H. Yoshida, Construction of higher order symplectic integrators, Phys. Lett. A, 150 (1990), 262-268.  doi: 10.1016/0375-9601(90)90092-3.  Google Scholar
Elements of order up to 6 of a generalized Hall basis $\mathcal H$ for $L(A,B)$. The elements in the Lie ideal $\mathcal{I}$ generated by $[L^0(A,B),L^0(A,B)]$ are depicted in red. The elements belonging to the basis $\mathcal B$ for $L_{\mathfrak P}(A,B) = L(A,B)/\mathcal{I}$ are depicted in black. The elements are listed in the total order defined in §2.3
 $U$ order$(U)$ degree$(U)$ $B$ 1 0 $[B,[B,A]]$ 3 0 ${[B,[B,[B,A]]]}$ 4 0 $[[B,[B,A]],[B,A]]$ 5 0 ${ [B,[B,[B,[B,A]]]]}$ 5 0 ${[[B,[B,[B,A]]],[B,A]]}$ 6 0 ${[B,[B,[B,[B,[B,A]]]]]}$ 6 0 $[B,A]$ 2 1 $[[B,[B,A]],A]$ 4 1 ${[[B,[B,[B,A]]],A]}$ 5 1 $[[[B,[B,A]],[B,A]],A ]$ 6 1 ${[[B,[B,[B,[B,A]]]],A]}$ 6 1 $[[B,A],[[B,[B,A]],A]]$ 6 1 $A$ 1 2 $[[B,A],A]$ 3 2 $[[[B,[B,A]],A],A]$ 5 2 $[[B,A],[[B,A],A]]$ 5 2 ${ [[[B,[B,[B,A]]],A],A]}$ 6 2 $[A,[[B,A],A]]$ 4 3 $[A,[[[B,[B,A]],A],A]]$ 6 3 $[A,[[B,A],[[B,A],A]]]$ 6 3 $[A,[A,[[B,A],A]]]$ 5 4 $[A,[A,[A,[[B,A],A]]]]$ 6 5
 $U$ order$(U)$ degree$(U)$ $B$ 1 0 $[B,[B,A]]$ 3 0 ${[B,[B,[B,A]]]}$ 4 0 $[[B,[B,A]],[B,A]]$ 5 0 ${ [B,[B,[B,[B,A]]]]}$ 5 0 ${[[B,[B,[B,A]]],[B,A]]}$ 6 0 ${[B,[B,[B,[B,[B,A]]]]]}$ 6 0 $[B,A]$ 2 1 $[[B,[B,A]],A]$ 4 1 ${[[B,[B,[B,A]]],A]}$ 5 1 $[[[B,[B,A]],[B,A]],A ]$ 6 1 ${[[B,[B,[B,[B,A]]]],A]}$ 6 1 $[[B,A],[[B,[B,A]],A]]$ 6 1 $A$ 1 2 $[[B,A],A]$ 3 2 $[[[B,[B,A]],A],A]$ 5 2 $[[B,A],[[B,A],A]]$ 5 2 ${ [[[B,[B,[B,A]]],A],A]}$ 6 2 $[A,[[B,A],A]]$ 4 3 $[A,[[[B,[B,A]],A],A]]$ 6 3 $[A,[[B,A],[[B,A],A]]]$ 6 3 $[A,[A,[[B,A],A]]]$ 5 4 $[A,[A,[A,[[B,A],A]]]]$ 6 5
Dimensions of Lie algebras graded by order. Column 2: Of the free Lie algebra with two generators. Column 3: Of the Lie algebra of classical mechanics, $L_\mathfrak P(A,B)$. Column 4: Dimensions $x_n$ of the subspace of elements of degree 0 in $L^n_\mathfrak P(A,B)$. Column 5: Dimensions $y_n$ of the subspace of elements of degree 1 in $L^n_\mathfrak P(A,B)$
 $n$ $\dim L^n(A,B)$ $\dim L^n_\mathfrak{P}(A,B)$ $x_n$ $y_n$ 1 2 2 1 2 1 1 1 3 2 2 1 4 3 2 2 5 6 4 1 6 9 5 4 7 18 10 2 8 30 14 9 9 56 25 3 10 99 39 18 11 186 69 6 12 335 110 41 13 630 193 11 14 1161 320 88 15 2182 555 23 16 4080 938 198 17 7710 1630 46 18 14532 2786 441 19 27594 4852 98 20 52377 8370
 $n$ $\dim L^n(A,B)$ $\dim L^n_\mathfrak{P}(A,B)$ $x_n$ $y_n$ 1 2 2 1 2 1 1 1 3 2 2 1 4 3 2 2 5 6 4 1 6 9 5 4 7 18 10 2 8 30 14 9 9 56 25 3 10 99 39 18 11 186 69 6 12 335 110 41 13 630 193 11 14 1161 320 88 15 2182 555 23 16 4080 938 198 17 7710 1630 46 18 14532 2786 441 19 27594 4852 98 20 52377 8370
Image by $\Theta$ and $\Phi_V$ of Prop.2 of elements in $L_\mathfrak{P}(A,B)$ of order up to 6. Repeated indices are summed from 1 to $d$
Dimensions of homogeneous subspaces of $L_\mathfrak P(A,B)$ of order $n$ (rows $n = 1,\ldots,18$) and degree $m-1$ (columns $m = 1,\ldots,18$)
 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 2 0 4 0 3 0 1 0 0 0 0 0 0 0 0 0 0 0 0 4 0 6 0 3 0 1 0 0 0 0 0 0 0 0 0 0 3 0 9 0 8 0 4 0 1 0 0 0 0 0 0 0 0 0 0 9 0 14 0 11 0 4 0 1 0 0 0 0 0 0 0 0 6 0 20 0 23 0 14 0 5 0 1 0 0 0 0 0 0 0 0 18 0 37 0 32 0 17 0 5 0 1 0 0 0 0 0 0 11 0 46 0 62 0 46 0 21 0 6 0 1 0 0 0 0 0 0 41 0 90 0 97 0 60 0 25 0 6 0 1 0 0 0 0 23 0 106 0 165 0 144 0 80 0 29 0 7 0 1 0 0 0 0 88 0 228 0 274 0 206 0 100 0 34 0 7 0 1 0 0 46 0 248 0 438 0 438 0 285 0 127 0 39 0 8 0 1 0 0 198 0 562 0 777 0 658 0 384 0 154 0 44 0 8 0 1
 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 2 0 4 0 3 0 1 0 0 0 0 0 0 0 0 0 0 0 0 4 0 6 0 3 0 1 0 0 0 0 0 0 0 0 0 0 3 0 9 0 8 0 4 0 1 0 0 0 0 0 0 0 0 0 0 9 0 14 0 11 0 4 0 1 0 0 0 0 0 0 0 0 6 0 20 0 23 0 14 0 5 0 1 0 0 0 0 0 0 0 0 18 0 37 0 32 0 17 0 5 0 1 0 0 0 0 0 0 11 0 46 0 62 0 46 0 21 0 6 0 1 0 0 0 0 0 0 41 0 90 0 97 0 60 0 25 0 6 0 1 0 0 0 0 23 0 106 0 165 0 144 0 80 0 29 0 7 0 1 0 0 0 0 88 0 228 0 274 0 206 0 100 0 34 0 7 0 1 0 0 46 0 248 0 438 0 438 0 285 0 127 0 39 0 8 0 1 0 0 198 0 562 0 777 0 658 0 384 0 154 0 44 0 8 0 1
Dimensions of homogeneous subspaces of $\mathcal T$ of order $n$ (rows $n = 1,\ldots,18$) and degree $m-1$ (columns $m = 1,\ldots,18$)
 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 2 0 4 0 3 0 1 0 0 0 0 0 0 0 0 0 0 0 0 4 0 6 0 3 0 1 0 0 0 0 0 0 0 0 0 0 3 0 10 0 9 0 4 0 1 0 0 0 0 0 0 0 0 0 0 9 0 17 0 12 0 4 0 1 0 0 0 0 0 0 0 0 6 0 24 0 30 0 16 0 5 0 1 0 0 0 0 0 0 0 0 20 0 50 0 44 0 20 0 5 0 1 0 0 0 0 0 0 11 0 63 0 96 0 67 0 25 0 6 0 1 0 0 0 0 0 0 48 0 146 0 164 0 91 0 30 0 6 0 1 0 0 0 0 23 0 164 0 315 0 267 0 126 0 36 0 7 0 1 0 0 0 0 115 0 437 0 592 0 408 0 163 0 42 0 7 0 1 0 0 47 0 444 0 1022 0 1059 0 603 0 213 0 49 0 8 0 1 0 0 286 0 1300 0 2126 0 1754 0 856 0 265 0 56 0 8 0 1
 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0 2 0 4 0 3 0 1 0 0 0 0 0 0 0 0 0 0 0 0 4 0 6 0 3 0 1 0 0 0 0 0 0 0 0 0 0 3 0 10 0 9 0 4 0 1 0 0 0 0 0 0 0 0 0 0 9 0 17 0 12 0 4 0 1 0 0 0 0 0 0 0 0 6 0 24 0 30 0 16 0 5 0 1 0 0 0 0 0 0 0 0 20 0 50 0 44 0 20 0 5 0 1 0 0 0 0 0 0 11 0 63 0 96 0 67 0 25 0 6 0 1 0 0 0 0 0 0 48 0 146 0 164 0 91 0 30 0 6 0 1 0 0 0 0 23 0 164 0 315 0 267 0 126 0 36 0 7 0 1 0 0 0 0 115 0 437 0 592 0 408 0 163 0 42 0 7 0 1 0 0 47 0 444 0 1022 0 1059 0 603 0 213 0 49 0 8 0 1 0 0 286 0 1300 0 2126 0 1754 0 856 0 265 0 56 0 8 0 1
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