“1.1/ Planetary Control
On any planet where the population is greater than (Planet size * Planet size * 2,500), the faction owning more than 50% of the flats of a planet, with these flats being all powered is considered the controlling power of that planet. The faction name will be displayed in the planet's information as being the legal owner of that planet.
If the majority of the flats is owned by NPCs or if the total population is strictly lower than (Planet size * Planet size * 2,500) the planet will remain neutral and 'None' will appear in the planet's information.
If a facility containing flats (house, high-rise...) is made over to or by a faction, then the owner is recalculated. Therefore, trading facilities may generate a change in owner, including the planet reverting to a neutral status. ”
This is what I found from the government page. Doesn't say anything about a minimum number of flats to build, just that I need >50% of the flats. Since there's no slabs or flats on a newly discovered system, it only needs one lowly little personal residence to claim it? Or do I need to build enough flats to fit the minimum population?