ar X iv : m at h - ph / 0 50 10 26 v 1 1 1 Ja n 20 05 Projective dynamics and classical gravitation
نویسنده
چکیده
Given a vector space V of finite dimension, together with a particular homogeneous field of bivectors that we call a field of projective forces, we define a law of dynamics such that the position of the particle is a ray i.e. a half-line drawn from the origin of V. The impulsion is a bivector whose support is a 2-plane containing the ray. Throwing the particle with a given initial impulsion defines a projective trajectory. It is a curve in the space of rays S(V), together with an impulsion attached to each ray. In the simplest example where the force is identically zero, the curve is a straight line and the impulsion a constant bivector in 2 V. A striking feature of projective dynamics appears: the tra-jectories are not parameterized. The next simplest specification of a projective force field defines the Kepler problem. An original point of view on the " hidden symmetries " of this problem emerges, and clarifies some remarks due to Halphen and Appell. We also get the unexpected conclusion that there exists a notion of divergence-free field of projective forces if and only if dim V = 4. No metric is involved in the axioms of projective dynamics.
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Given a real vector space V of finite dimension, together with a particular homogeneous field of bivectors that we call a field of projective forces, we define a law of dynamics such that the position of the particle is a ray i.e. a half-line drawn from the origin of V. The impulsion is a bivector whose support is a 2-plane containing the ray. Throwing the particle with a given initial impulsio...
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تاریخ انتشار 2005