There is a very good chance that Brian is a frog. It is certain that Greg is yellow. There is almost no chance that Julius is a lion. It is probably the case that if 'Julius is a lion' or 'Greg is yellow' or both then John put down the milk. Chances are about even that if either 'Greg is yellow' or 'Julius is a lion' but not both then Fred left the apple. It is probably the case that if either 'Julius is a lion' or 'Greg is yellow' but not both then Emily is a mouse.
There is almost no chance that 'Julius is a lion and Greg is yellow'.
There is almost no chance that 'Julius is a lion and Greg is yellow'.
Chances are about even that 'Julius is a lion and Greg is yellow'.

  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
  0.8::factA.
  1.0::factB.
  0.02::factC.
  %hop1
  0.7::factX:-or(factC,factB).
  0.5::factY:-xor(factB,factC).
  0.7::factZ:-xor(factC,factB).

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

  query(conclusion).
  
'Julius is a lion and Greg is yellow'.