Chances are about even that Bernhard is a lion. Chances are slight that Brian is gray. We doubt that Jessica is a cat. It is highly unlikely that if 'Bernhard is a lion and Brian is gray' then Lily is a swan. We doubt that if 'Bernhard is a lion' or 'Jessica is a cat' or both then Greg is white. It is certain that if 'Jessica is a cat' or 'Bernhard is a lion' or both then Daniel left the milk.
There is almost no chance that 'Jessica is a cat and Brian is gray'.
There is almost no chance that 'Jessica is a cat and Brian is gray'.
It is likely that 'Jessica is a cat and Brian is gray'.

  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
  0.5::factA.
  0.1::factB.
  0.2::factC.
  %hop1
  0.05::factX:-and(factA,factB).
  0.2::factY:-or(factA,factC).
  1.0::factZ:-or(factC,factA).

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

  query(conclusion).
  
'Jessica is a cat and Brian is gray'.