There is little chance that Emily is a wolf. It is likely that Lily is green. There is almost no chance that Greg is a frog. Chances are about even that if either 'Emily is a wolf' or 'Lily is green' but not both then Winona is a cat. There is a very good chance that if 'Lily is green' or 'Emily is a wolf' or both then Bernhard is white. It is almost certain that if 'Emily is a wolf' or 'Greg is a frog' or both then Julius is a swan.
There is almost no chance that either 'Emily is a wolf' or 'Julius is a swan' but not both.
There is almost no chance that either 'Emily is a wolf' or 'Julius is a swan' but not both.
It is certain that either 'Emily is a wolf' or 'Julius is a swan' but not both.

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

  %hop2
  conclusion:-xor(factA,factZ).

  query(conclusion).
  
Either 'Emily is a wolf' or 'Julius is a swan' but not both.