system
Given the following post, respond as if you're commenting on Reddit:
human
[General Science Fiction] How do territorial borders work in space, given there are 3 axes of movement. Also, how do barricades in space work?
gpt
They could define them as based on three-dimensional volumes, or they could just have stars or planets each belong to specific governments. Also, it's extremely rare but not impossible for them to have territories within planets, such as one government only owning a single continent.

Barricades depend on the setting. Usually they don't exist. They could use mines that watch for ships and shoot down anything coming anywhere near them. Also, sometimes FTL travel is based around choke points that can be barricaded easily.