## metricAny function d( x, y) that describes the distance between two
points. Distance is formally defined as a single number with the following
properties: (1) d(x, y) = 0 if and only if x = y;
(2) d(x, y) = d(y, x); (3) d(x, y)
+ d(y, z) > or = d(x, z) (the triangle inequality).
The concept of a metric is important in differential
geometry.## Related categories• GEOMETRY• GRAVITATIONAL PHYSICS • SPACE AND TIME | |||||

Home • About • Copyright © The Worlds of David Darling • Encyclopedia of Alternative Energy • Contact |