By default, the original creator of an object is its owner. The User who created a Page or Community is the owner. It should go without saying that Users cannot be owned by anyone except themselves. That would be slavery and that's bad. Perhaps ownership will be shown as a breadcrumb. 

Ownership rights

• Owners approve edit proposals submitted to them. By default all pages can be edited, but those edits are not live until the owner approves those edits.

• Owners can transfer ownership to another User or to a Community.

• Owners can set certain Users to have their edits automatically approved.