It is probably not the case that Mary went to the hallway. It is highly likely that Brian is yellow. It is unlikely that Julius is a swan. There is a very good chance that if 'Brian is yellow and Mary went to the hallway' then Greg is a lion. It is unlikely that if 'Julius is a swan and Mary went to the hallway' then Daniel left the milk. It is highly unlikely that if either 'Julius is a swan' or 'Mary went to the hallway' but not both then Bernhard is gray.
It is probably the case that 'Julius is a swan and Daniel left the milk'.
There is almost no chance that 'Julius is a swan and Daniel left the milk'.
It is probably the case that 'Julius is a swan and Daniel left the milk'.

  and(A,B) :- A,B.
  or(A,B) :- A;B.
  nand(A,B) :- not(and(A,B)).
  nor(A,B) :- not(or(A,B)).
  xor(A,B) :- or(A,B), nand(A,B).

  %hop0
  0.25::factA.
  0.9::factB.
  0.2::factC.
  %hop1
  0.8::factX:-and(factB,factA).
  0.2::factY:-and(factC,factA).
  0.05::factZ:-xor(factC,factA).

  %hop2
  conclusion:-and(factC,factY).

  query(conclusion).
  
'Julius is a swan and Daniel left the milk'.