Initial clauses:

Use notation card(place,name) to indicate that a particular card is in
a particular place. For example, card(mu,re) means that that player
Col. Mustard is holding the revolver card, and card(cf,st) means that
the case file has the study card. For each of these parts, there are a
LOT of clauses. You don't need to write each one: you just need to
show that you've got the pattern figured out. I've provided a sample
complete answer for the first part (each card in at least one place)
-- you should complete parts 2, 3, and 4.

Make sure that your knowledge base is in CNF: each individual rule
should be a disjunct (a collection of things connection by "or").

1. Each card in at least one place (including case file)

card(mu,ha) V card(pl,ha) V card(gr,ha) V card(pe,ha) V
              card(sc,ha) V card(wh,ha) V card(cf,ha)
  [the "hall" card is in at least one place]

card(mu,lo) V card(pl,lo) V card(gr,lo) V card(pe,lo) V
              card(sc,lo) V card(wh,lo) V card(cf,lo)
  [the "lounge" card is in at least one place]

... and similarly all rooms, knives, and _players_ (this one is easy
to miss). For example:

card(mu,mu) V card(pl,mu) V card(gr,mu) V card(pe,mu) V
              card(sc,mu) V card(wh,mu) V card(cf,mu)
  [the "Col. Mustard" card is in at least one place]


2. If a card is in one place, it cannot be in another place.




3. At least one card of each category is in the case file.




4. No two cards in each category can both be in the case file.