We believe that Fred went to the garden. It is highly likely that Greg is green. Chances are slight that Brian is white. There is almost no chance that if 'Brian is white' or 'Greg is green' or both then Lily is a rhino. There is a very good chance that if either 'Brian is white' or 'Fred went to the garden' but not both then Yann is hungry. It is highly unlikely that if 'Brian is white' or 'Fred went to the garden' or both then John got the apple.
There is almost no chance that 'Yann is hungry and Lily is a rhino'.
There is almost no chance that 'Yann is hungry and Lily is a rhino'.
It is certain that 'Yann is hungry and Lily 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
  0.75::factA.
  0.9::factB.
  0.1::factC.
  %hop1
  0.02::factX:-or(factC,factB).
  0.8::factY:-xor(factC,factA).
  0.05::factZ:-or(factC,factA).

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

  query(conclusion).
  
'Yann is hungry and Lily is a rhino'.