Long-term consequences of observing an expanding cosmological civilization.

"What sort of boundary forms between their expanding domains, and how does the presence of one limit the ambitions of another? "

"If a domain is visible at the time one embarks on expansion, there exists an optimum value for the "practical speed limit," and if the speed limit is much higher than optimal, one's future will be severely limited. In the case of two visible domains, it is possible to be "trapped" by them if the practical speed limit is high enough and their angular separation in the sky is large enough, i.e. one's expansion in any direction will terminate at a boundary with the two visible civilizations. "

http://arxiv.org/abs/1608.07522