There is little chance that Brian is a rhino. It is highly likely that Lily is white. We believe that Winona is a sheep. It is highly unlikely that if 'Brian is a rhino' or 'Winona is a sheep' or both then John went to the garden. There is a better than even chance that if 'Brian is a rhino and Lily is white' then Mary left the apple. It is certain that if 'Brian is a rhino' or 'Lily is white' or both then Greg is yellow.
It is highly unlikely that 'Lily is white and Mary left the apple'.
It is highly unlikely that 'Lily is white and Mary left the apple'.
It is certain that 'Lily is white and Mary left the apple'.

  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.
  0.9::factB.
  0.75::factC.
  %hop1
  0.05::factX:-or(factA,factC).
  0.6::factY:-and(factA,factB).
  1.0::factZ:-or(factA,factB).

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

  query(conclusion).
  
'Lily is white and Mary left the apple'.