It is impossible that Lily is a lion. It is impossible that Julius is gray. Chances are slight that Sandra left the milk. It is improbable that if 'Lily is a lion' or 'Sandra left the milk' or both then John dropped the apple. It is probably not the case that if 'Julius is gray' or 'Lily is a lion' or both then Gertrude is a cat. It is certain that if 'Sandra left the milk and Julius is gray' then Bernhard is yellow.
It is impossible that 'Julius is gray and Lily is a lion'.
It is impossible that 'Julius is gray and Lily is a lion'.
It is probably the case that 'Julius is gray and Lily is a lion'.

  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.
  0.0::factB.
  0.1::factC.
  %hop1
  0.1::factX:-or(factA,factC).
  0.25::factY:-or(factB,factA).
  1.0::factZ:-and(factC,factB).

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

  query(conclusion).
  
'Julius is gray and Lily is a lion'.