It is impossible that Bernhard is yellow. It is unlikely that Lily is white. There is little chance that Brian is a swan. It is impossible that if either 'Bernhard is yellow' or 'Lily is white' but not both then Julius is green. It is certain that if either 'Bernhard is yellow' or 'Brian is a swan' but not both then Jessica is a mouse. It is likely that if either 'Brian is a swan' or 'Bernhard is yellow' but not both then John left the milk.
There is a better than even chance that 'Lily is white and Brian is a swan'.
There is almost no chance that 'Lily is white and Brian is a swan'.
There is a better than even chance that 'Lily is white and Brian is a swan'.

  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
  0.0::factA.
  0.2::factB.
  0.1::factC.
  %hop1
  0.0::factX:-xor(factA,factB).
  1.0::factY:-xor(factA,factC).
  0.7::factZ:-xor(factC,factA).

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

  query(conclusion).
  
'Lily is white and Brian is a swan'.