causal boundary

causal boundary

[¦kȯz·əl ′bau̇n·drē]
(relativity)
A boundary attached to a space-time that depends only on the causal structure; it does not distinguish between boundary points at finite distances (singularities) or those at infinity. Also known as C boundary.
References in periodicals archive ?
We notice that in the action formalism variations of metric tensor should be limited by the Hubble horizon, which represents a causal boundary of classical spacetime.
McNabb, An initial value theory for linear causal boundary value problems, Journal of Differential Equations 15(1974) 322-349.
They also introduce the new Busemann compactification, relating it to the previous two completions, and give a full description of the causal boundary of any standard conformally stationary spacetime.