It is unlikely that Brian is a rhino. It is probably the case that Julius is a lion. We believe that Mary got the apple. It is certain that if 'Mary got the apple and Brian is a rhino' then Bill left the football. There is almost no chance that if either 'Mary got the apple' or 'Brian is a rhino' but not both then Fred went to the garden. There is almost no chance that if 'Mary got the apple and Brian is a rhino' then Lily is a swan.
It is impossible that 'Julius is a lion and Lily is a swan'.
It is impossible that 'Julius is a lion and Lily is a swan'.
We believe that 'Julius is a lion and Lily 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
  0.2::factA.
  0.7::factB.
  0.75::factC.
  %hop1
  1.0::factX:-and(factC,factA).
  0.02::factY:-xor(factC,factA).
  0.02::factZ:-and(factC,factA).

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

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