It is highly likely that Julius is a frog. There is almost no chance that John picked up the apple. It is highly likely that Fred left the football. It is highly unlikely that if 'Julius is a frog and John picked up the apple' then Lily is yellow. There is almost no chance that if 'Julius is a frog' or 'Fred left the football' or both then Bernhard is a lion. It is certain that if either 'Julius is a frog' or 'Fred left the football' but not both then Brian is a swan.
It is probable that 'Lily is yellow and Bernhard is a lion'.
It is impossible that 'Lily is yellow and Bernhard is a lion'.
It is probable that 'Lily is yellow and Bernhard is a lion'.

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

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

  query(conclusion).
  
'Lily is yellow and Bernhard is a lion'.