 Another interesting line of research is triggered by the theory of branching space-times developed in Belnap (1992). This theory relates to space-time just as Prior’s theory of branching time relates to linear time; that is, it combines space-time reasoning with indeterminism. See e.g. Müller (2013) and Placek (2014), where the topology of branching space-times is studied against the background of relativity theory. An extensive overview of branching space-times can be found in Belnap et al. (2022).