Affine Structure
Affine Structure
Although Sklar made only a passing remark (49), the notion of affine structure is important for understanding many crucial statements about spacetime theories in recent lieterature, such as Friedman (1983). Informally, the affine structure of the given spacetime specifies which of the curves in the spacetime are the "straight lines", not presupposing the metric of the spacetime yet. That is, we can separate the notion of "straight line" or "geodesic" and the notion of metric, and the affine structure is concerned only with the former. A space (or spacetime) which has an affine structure is an affine space, as Sklar said.
Last modified Sept. 20, 2007. (c) Soshichi Uchii
