Abstract
The chapter focusses of some basic ideas in the geometry of Hörmander’s vector fields. We start with a discussion of the basic concept of connectivity, and some of its physical meanings which have been known for a long time. We then pass to survey some ideas and fundamental results about the metric induced by a system of vector fields, which are contained in some papers of the middle 1980’s. This area is by a now an independent field of study, but here we are mainly interested in its relevance in connection with the study of second order PDEs of Hörmander’s type.
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Notes
- 1.
The original paper by Carathéodory is [7], in German. An English translation can be found in the book [25, Chap. 12]. To the reader who is interested in Carathéodory’s ideas on thermodynamics, however, I suggest the reading of some parts of an essay written by Max Born on that subject, see [4, Chap. V and Appendix 6, 7].
- 2.
Recall that one of Hilbert’s problems posed in the international congress of mathematics held in Paris in 1900 consisted in giving an axiomatization of physical theories, following the general trend to axiomatization which pervaded mathematics in those years.
- 3.
Here we follow the simplified presentation of the theory given in [4, Chap. 5]; Carathéodory’s approach is more general and abstract, and involves Pfaffian forms of \(n\) variables.
- 4.
For an overview of the subject I particularly suggest the reading of Jurdjevic’ introduction to his book and the introduction to Chap. 1.
- 5.
A clear example of such control system is rowing a boat on a river: the river’s drift is out of our control.
- 6.
Actually, Gromov in [19, p. 87] suggests that some form of the connectivity theorem could be known to Lagrange in the context of nonholonomic mechanics.
- 7.
The reader will recognize some analogy with the controllability problem for an affine control system with drift, discussed in the previous paragraph.
- 8.
Actually the authors prove the equivalence between five different distances, but here we will concentrate just on two of them.
- 9.
The first use of this term appeared in Gromov’ book of 1981 “Structures métriques pour les variétés riemanniennes” (edited by J. Lafontaine and P. Pansu), later transformed in [20].
- 10.
Gromov refers to the 1981 edition of [20], see the previous footnote.
- 11.
The following bibliographical account is quoted from [5, p. 3].
References
Agrachev, A.A., Sachkov, Y.L.: Control theory from the geometric viewpoint. Encyclopaedia of Mathematical Sciences, vol. 87. Control Theory and Optimization, II. Springerg, Berlin (2004)
Bloch, A.M.: Nonholonomic mechanics and control. With the collaboration of J. Baillieul, P. Crouch and J. Marsden. With scientific input from P. S. Krishnaprasad, R. M. Murray and D. Zenkov. Interdisciplinary Applied Mathematics, vol. 24. Systems and Control. Springer, New York (2003)
Bony, J.M.: Principe du maximum, inégalite de Harnack et unicité du problème de Cauchy pour les opérateurs elliptiques dégénérés. Ann. Inst. Fourier (Grenoble) 19 1969 fasc. 1, 277–304 xii
Born, M.: Natural Philosophy of Cause and Chance. Clarendon Press, Oxford (1948)
Bramanti, M., Brandolini, L., Lanconelli, E., Uguzzoni, F.: Non-divergence equations structured on Hörmander vector fields: heat kernels and Harnack inequalities. Mem. AMS 204(961), 1–136 (2010)
Calin, O., Chang, D.-C.: Sub-Riemannian geometry. General theory and examples. Encyclopedia of Mathematics and its Applications, vol. 126. Cambridge University Press, Cambridge (2009)
Carathéodory, C.: Untersuchungen über die Grundlagen der Thermodynamik. Math. Ann. 67(3), 355–386 (1909). An English translation can be found in the book [25, Chap. 12]
Chow, W.-L.: Über Systeme von linearen partiellen Differentialgleichungen erster Ordnung. Math. Ann. 117, 98–105 (1939)
Fabes, E.B., Kenig, C.E., Serapioni, R.P.: The local regularity of solutions of degenerate elliptic equations. Comm. Partial Differ. Equ. 7(1), 77–116 (1982)
Fefferman, C., Sánchez-Calle, A.: Fundamental solutions for second order subelliptic operators. Ann. Math. (2) 124(2), 247–272 (1986)
Franchi, B.: BV spaces and rectifiability for Carnot-Carathéodory metrics: an introduction. Notes for a course at the Spring School on Nonlinear Analysis, Function Spaces and Applications 7, Prague, July 17–22, 2002. Downloadable at: http://www.mate.polimi.it/scuolaestiva/bibliografia/franchi_corso_NAFSA7.pdf
Franchi, B., Lanconelli, E.: De Giorgi’s theorem for a class of strongly degenerate elliptic equations. Atti Accad. Naz. Lincei Rend. Cl. Sci. Fis. Mat. Natur. (8) 72 (1982), no. 5, 273–277 (1983)
Franchi, B., Lanconelli, E.: Hölder regularity theorem for a class of linear nonuniformly elliptic operators with measurable coefficients. Ann. Scuola Norm. Sup. Pisa Cl. Sci. (4) 10(4), 523–541 (1983)
Franchi, B., Lanconelli, E.: Une condition géométrique pour l’inégalité de Harnack. J. Math. Pures Appl. (9) 64(3), 237–256 (1985)
Franchi, B., Lanconelli, E.: Une métrique associée à une classe d’opérateurs elliptiques dégénérés. In: Conference on Linear Partial and Pseudodifferential Operators (Torino, 1982). Rend. Sem. Mat. Univ. Politec. Torino 1983, Special Issue, 105–114 (1984)
Franchi, B., Lanconelli, E.: An embedding theorem for Sobolev spaces related to nonsmooth vector fields and Harnack inequality. Comm. Partial Differ. Equ. 9(13), 1237–1264 (1984)
Franchi, B., Lu, G., Wheeden, R.L.: A relationship between Poincaré-type inequalities and representation formulas in spaces of homogeneous type. Int. Math. Res. Not. 1, 1–14 (1996)
Garofalo, N., Nhieu, D.-M.: Isoperimetric and Sobolev inequalities for Carnot-Carathéodory spaces and the existence of minimal surfaces. Comm. Pure Appl. Math. 49(10), 1081–1144 (1996)
Gromov, M.: Carnot-Carathéodory spaces seen from within. Sub-Riemannian geometry, pp. 79–323, Progr. Math., 144, Birkhäuser, Basel (1996)
Gromov, M.: Metric structures for Riemannian and Non Riemannian Spaces, Progress in Mathematics, vol. 152. Birkhauser Verlag, Boston (1999)
Hajlasz, P., Koskela, P.: Sobolev met Poincaré. Mem. Am. Math. Soc. 145(688) (2000)
Jerison, D.: The Poincaré inequality for vector fields satisfying Hörmander’s condition. Duke Math. J. 53(2), 503–523 (1986)
Jerison, D., Sánchez-Calle, A.: Estimates for the heat kernel for a sum of squares of vector fields. Indiana Univ. Math. J. 35(4), 835–854 (1986)
Jurdjevic, V.: Geometric control theory. Cambridge Studies in Advanced Mathematics, vol. 52. Cambridge University Press, Cambridge (1997)
Kestin, J. (ed.): The Second Law of Thermodynamics. Dowden, Hutchinson & Ross, Inc. Stroudsburg, Pennsylvania (1976)
Kusuoka, S., Stroock, D.: Applications of the Malliavin calculus. III. J. Fac. Sci. Univ. Tokyo Sect. IA Math. 34(2), 391–442 (1987)
Kusuoka, S., Stroock, D.: Long time estimates for the heat kernel associated with a uniformly subelliptic symmetric second order operator. Ann. Math. (2) 127(1), 165–189 (1988)
Montgomery, R.: A tour of subriemannian geometries, their geodesics and applications. Mathematical Surveys and Monographs, vol. 91. American Mathematical Society, Providence (2002)
Murray, R.M., Sastry, S.S.: Nonholonomic motion planning: steering using sinusoids. IEEE Trans. Automat. Control 38(5), 700–716 (1993)
Nagel, A., Stein, E.M., Wainger, S.: Balls and metrics defined by vector fields. I. Basic properties. Acta Math. 155(1–2), 103–147 (1985)
Rashevski, P.K.: Any two points of a totally nonholonomic space may be connected by an admissible line. Uch. Zap. Ped. Inst. im. Liebknechta, Ser. Phys. Mat. 2, 83–94 (1938)
Rothschild, L.P., Stein, E.M.: Hypoelliptic differential operators and nilpotent groups. Acta Math. 137(3–4), 247–320 (1976)
Saloff-Coste, L.: A note on Poincaré, Sobolev, and Harnack inequalities. Internat. Math. Res. Notices , no. 2, 27–38 (1992)
Saloff-Coste, L., Stroock, D.W.: Opérateurs uniformément sous-elliptiques sur les groupes de Lie. J. Funct. Anal. 98(1), 97–121 (1991)
Sánchez-Calle, A.: Fundamental solutions and geometry of the sum of squares of vector fields. Invent. Math. 78(1), 143–160 (1984)
Sawyer, E.T., Wheeden, R.L.: Hölder continuity of weak solutions to subelliptic equations with rough coefficients. Mem. Am. Math. Soc. 180(847) (2006)
Varopoulos, N.Th., Saloff-Coste, L., Coulhon, T.: Analysis and geometry on groups. Cambridge Tracts in Mathematics, vol. 100. Cambridge University Press, Cambridge (1992)
Varopoulos, N.Th.: Analysis on nilpotent groups. J. Funct. Anal. 66(3), 406–431 (1986)
Varopoulos, N.Th.: Théorie du potentiel sur les groupes nilpotents. C. R. Acad. Sci. Paris Sér. I Math. 301(5), 143–144 (1985)
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Bramanti, M. (2014). Geometry of Hörmander’s Vector Fields. In: An Invitation to Hypoelliptic Operators and Hörmander's Vector Fields. SpringerBriefs in Mathematics. Springer, Cham. https://doi.org/10.1007/978-3-319-02087-7_4
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