Einstein's Relativity and the Geometries of the Plane

This text considers the geometrical properties of space and time from the viewpoint of mechanics and cosmology. Concentrating on the boundary between geometry and physics, it focuses on the border region which can be neglected in works on either fields.

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Philosophers, physicists and mathematicians - Kant, Helmholtz, Einstein and Hilbert - have written about the connection between physics and geometry. This text is an elementary illustration of this fundamental question. It considers the geometrical properties of space and time from the viewpoint of mechanics and cosmology. Concentrating on the boundary between geometry and physics, it focuses on the border region which can be neglected in works on either fields. The reader needs only a college acquaintance with geometry and mechanics.