e/Congruence (general relativity)

Information
has gloss	eng: In general relativity, a congruence (more properly, a congruence of curves) is the set of integral curves of a (nowhere vanishing) vector field in a four-dimensional Lorentzian manifold which is interpreted physically as a model of spacetime. Often this manifold will be taken to be an exact or approximate solution to the Einstein field equation.
lexicalization	eng: congruence
instance of	c/Mathematical methods in general relativity