There is little chance that Sandra dropped the milk. It is probably not the case that Julius is yellow. It is probably the case that Brian is a lion. It is highly unlikely that if 'Julius is yellow and Brian is a lion' then Greg is a rhino. We believe that if 'Sandra dropped the milk and Julius is yellow' then Jessica is a cat. There is little chance that if 'Brian is a lion' or 'Sandra dropped the milk' or both then John took the apple.
It is highly likely that 'Brian is a lion and Greg is a rhino'.
It is impossible that 'Brian is a lion and Greg is a rhino'.
It is highly likely that 'Brian is a lion and Greg 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
  0.1::factA.
  0.25::factB.
  0.7::factC.
  %hop1
  0.05::factX:-and(factB,factC).
  0.75::factY:-and(factA,factB).
  0.1::factZ:-or(factC,factA).

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

  query(conclusion).
  
'Brian is a lion and Greg is a rhino'.