Public- government properties that government is constitutionally required to make available for speech (parks, etc.)
Test- 1.) regulation must be content neutral, 2.) narrowly tailored, 3.) serves important government interest, and 4.) leaves open alternate means.
Non-Public - place that are not open to the public such as military bases, sidewalks outside post offices, etc.
Test- 1.) must be viewpoint neutral and 2.) reasonably related to legitimate gov purpose.
Limited Public Forum aka designated public forum - public ppty not traditionally open to speech related activities, but which the gov has thrown open for such activities.
Test- same as public