There is little chance that Brian is a frog. We believe that Greg is green. There is a better than even chance that Mary dropped the apple. It is certain that if 'Brian is a frog' or 'Greg is green' or both then Julius is a swan. It is improbable that if either 'Mary dropped the apple' or 'Greg is green' but not both then John went to the bedroom. There is a better than even chance that if 'Greg is green' or 'Mary dropped the apple' or both then Lily is a rhino.
It is certain that 'Lily is a rhino and Brian is a frog'.
It is highly unlikely that 'Lily is a rhino and Brian is a frog'.
It is certain that 'Lily is a rhino and Brian 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
  0.1::factA.
  0.75::factB.
  0.6::factC.
  %hop1
  1.0::factX:-or(factA,factB).
  0.1::factY:-xor(factC,factB).
  0.6::factZ:-or(factB,factC).

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

  query(conclusion).
  
'Lily is a rhino and Brian is a frog'.