It is likely that Julius is green. It is unlikely that Lily is a swan. We believe that Greg is gray. There is a better than even chance that if either 'Lily is a swan' or 'Greg is gray' but not both then Mary picked up the apple. We doubt that if 'Julius is green' or 'Lily is a swan' or both then Gertrude is a sheep. There is a very good chance that if either 'Greg is gray' or 'Julius is green' but not both then John got the milk.
It is probable that 'Lily is a swan and Greg is gray'.
Chances are slight that 'Lily is a swan and Greg is gray'.
It is probable that 'Lily is a swan and Greg is gray'.

  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
  0.7::factA.
  0.2::factB.
  0.75::factC.
  %hop1
  0.6::factX:-xor(factB,factC).
  0.2::factY:-or(factA,factB).
  0.8::factZ:-xor(factC,factA).

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

  query(conclusion).
  
'Lily is a swan and Greg is gray'.