It is certain that Bernhard is a rhino. There is almost no chance that Brian is a lion. We believe that John got the milk. It is likely that if 'Bernhard is a rhino and John got the milk' then Gertrude is a sheep. It is probable that if either 'John got the milk' or 'Bernhard is a rhino' but not both then Julius is a swan. It is impossible that if 'Brian is a lion and Bernhard is a rhino' then Greg is a frog.
It is almost certain that 'Bernhard is a rhino and Greg is a frog'.
It is impossible that 'Bernhard is a rhino and Greg is a frog'.
It is almost certain that 'Bernhard is a rhino and Greg is a frog'.

  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
  1.0::factA.
  0.02::factB.
  0.75::factC.
  %hop1
  0.7::factX:-and(factA,factC).
  0.7::factY:-xor(factC,factA).
  0.0::factZ:-and(factB,factA).

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

  query(conclusion).
  
'Bernhard is a rhino and Greg is a frog'.