Invariant parametrizations and complete systems of global invariants of curves in the pseudo-Euclidean geometry

Let M(n, p) be the group of all transformations of an n-dimensional pseudo-Euclidean space Enp of index p generated by all pseudo-orthogonal transformations and parallel translations of Enp. Definitions of a pseudo-Euclidean type of a curve, an invariant parametrization of a curve and an M(n, p)-equivalence of curves are introduced. All possible invariant parametrizations of a curve with a fixed pseudo-Euclidean type are described. The problem of the M(n, p)-equivalence of curves is reduced to that of paths. Global conditions of the M(n, p)-equivalence of curves are given in terms of the pseudo-Euclidean type of a curve and the system of polynomial differential M(n, p)-invariants of a curve x(s).

Invariant parametrizations and complete systems of global invariants of curves in the pseudo-Euclidean geometry

Let M(n, p) be the group of all transformations of an n-dimensional pseudo-Euclidean space Enp of index p generated by all pseudo-orthogonal transformations and parallel translations of Enp. Definitions of a pseudo-Euclidean type of a curve, an invariant parametrization of a curve and an M(n, p)-equivalence of curves are introduced. All possible invariant parametrizations of a curve with a fixed pseudo-Euclidean type are described. The problem of the M(n, p)-equivalence of curves is reduced to that of paths. Global conditions of the M(n, p)-equivalence of curves are given in terms of the pseudo-Euclidean type of a curve and the system of polynomial differential M(n, p)-invariants of a curve x(s).

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  • Remark 7 According to Corollary 2, the system L(α), sgn < x, x>, < x(2), x(2)>, . . . , < x(n −1) , x(n −1) >,xx(2). . . x(n) is a complete system of SM (n, p) -invariants of a curve α for the case L(α) = (−∞, +∞). But they are not invariants of a curve α for the case L(α) = (−∞, +∞). They depend on reparametrizations s → s + a of the curve α . Aripov, R. G. and Khadzhiev, D.:, The complete system of differential and integral invariants of a curve in Euclidean geometry. Russian Mathematics (Iz VUZ), 51 , No. 7, 1-14 (2007).
  • Aslaner, R. and Boran, A. I.: On the geometry of null curves in the Minkowski 4-space. Turkish J. of Math. 32, 8 (2008).
  • Bejancu, A.: Lightlike curves in Lorentz manifolds. Publ. Math. Debrecen. 44, 145-155 (1994).
  • B´erard B. L. and Charuel X.: A generalization of Frenet’s frame for nondegenerate quadratic forms with any index. In: S´eminaire de th´eorie spectrale et g´eom´etrie. Ann´ee 2001-2002, St. Martin d’H´eres: Universit´e de Grenoble I,
  • Institut Fourier, S´emin. Th´eor. Spectr. G´eom. 20, 101-130 (2002).
  • Bini, D., Geralico, A. and Jantzen, R. T.: Frenet-Serret formalism for null world lines. Class. Quantum Grav. 23, 3981 (2006).
  • Bonnor, W.: Null curves in a Minkowski spacetime. Tensor, N. S. 20, 229-242 (1969).
  • Borisov Yu. F.: Relaxing the a priori constraints of the fundamental theorem of space curves in Enl. Siberian Math. J. 38, No. 3, 411-427 (1997).
  • Borisov Yu. F.: On the theorem of natural equations of a curve. Siberian Math. J. 40, No. 4, 617-621 (1999).
  • C¸ ¨oken, C. and C¸ ift¸ci, ¨U.: On the Cartan curvatures of a null curve in Minkowski spacetime. Geometriae Dedicata. , 71-78 (2005).
  • Duggal, K. L. and Becancu A.: Lightlike Submanifolds of Semi-Riemannian Manifolds and Applications. Dordrecht, Boston, London. Kluwer Acad. Publ. 1996.
  • Ferr´andez, A., Gim´enez, A. and Lucas, P.: Degenerate curves in pseudo-Euclidean spaces of index two. In: Mladenov, Ivailo M. (ed.) et al., Proceedings of the 3rd international conference on geometry, integrability and quantization, Varna, Bulgaria, June 14-23, 2001. SoŞa: Coral Press ScientiŞc Publishing. 209-223 (2002).
  • Ferr´andez, A., Gim´enez, A. and Lucas, P.: s -degenerate curves in Lorentzian space forms. J. Geom. Phys. 45, No. 2, 116-129 (2003).
  • Formiga, L. B. and Romero, C.: On the differential geometry of time-like curves in Minkowski spacetime. Am. J. Phys. 74(10), 1012-1016 (2006).
  • Ichimura, H.: Time-like and space-like curves in Frenet-Serret formalisms. Thesis. Hadronic J. Suppl. 3, No. 1, 1-94 (1987).
  • Kaplansky, I.: An Introduction to Differential Algebra. Paris. Hermann 1957.
  • Khadjiev, D. and Pek¸sen ¨O.: The complete system of global integral and differential invariants for equi-affine curves. Differential Geometry and its Applications. 20, 167-175 (2004).
  • Pek¸sen ¨O. and Khadjiev, D.: On invariants of curves in centro-affine geometry. J. Math. Kyoto Univ. (JMKYAZ). 3, 603-613 (2004).
  • Petrovi´c-Torga˘sev, Ilarslan K. and Ne˘sovi´c E.: On partially null and pseudo-null curves in the semi-euclidean space R4. J. Geom. 84, 106-116 (2005).
  • Spivak, M.: A Comprehensive Introduction to Differential Geometry, Vol.2. Berkeley, CA. Publ. of Perish. Inc. Urbantke H.: Local differential geometry of null curves in conformally flat space-time. J. Math. Phys. 30(10), 2245 (1989).
  • Yılmaz, S. and Turgut, M.: On the differential geometry of curves in Minkowski space-time I. Int. J. Contemp. Math. Sciences. 3, No. 27, 1343-1349 (2008). ¨
  • Omer PEKS¸EN, Djavvat KHADJIEV, ˙Idris ¨OREN Department of Mathematics Karadeniz Technical University, Trabzon-TURKEY e-mail: peksen@ktu.edu.tr; haciyev@ktu.edu.tr; oren@ktu.edu.tr