It is impossible that Brian is a rhino. It is certain that Gertrude is a wolf. There is almost no chance that Julius is a swan. Chances are about even that if 'Gertrude is a wolf and Brian is a rhino' then Bernhard is yellow. It is probably not the case that if 'Brian is a rhino' or 'Gertrude is a wolf' or both then John went to the office. It is unlikely that if 'Brian is a rhino and Julius is a swan' then Sandra got the milk.
It is almost certain that 'Gertrude is a wolf and Brian is a rhino'.
It is impossible that 'Gertrude is a wolf and Brian is a rhino'.
It is almost certain that 'Gertrude is a wolf and Brian is a rhino'.

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

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

  query(conclusion).
  
'Gertrude is a wolf and Brian is a rhino'.