Extendible spacetime
= Extendible spacetime
= Extendible
{synonym}
An <extendible spacetime> admits a <spacetime extension> in the specified regularity class. A coordinate horizon need not obstruct an extension: the exterior Schwarzschild chart extends through its horizon in regular null coordinates. Maximality refers to extensions of the given spacetime, not to the mere absence of a singularity in one coordinate chart.