Well yes, and if we're aiming for mathematical precision, we also need to define "cannot be removed". Beginners might naively think outside liberty=removable, inside=not removable, and would be wrong.

Someone looked at the page three edits ago and felt it wasn't clear enough as it stood, so they added "separate". I think they have a point, even if it's technically redundant.

This is an introductory level page, so I think we want something simple rather than long and Jasiek-level accurate. What's our best option? Feel free to revert to the earlier version, or edit to a new version if you have an idea.