Trying to get all the cases of and for is extremely tough, or I'm looking at it wrong.
The main issue is this: if , and if (at least according to another source). Trying to find all the least upper bounds and greatest lower bounds from those is insane, if not impossible. I don't even have a source to work off of in relation to the concept.
Really, I don't have a clue how we're supposed to do this.