It is unlikely that Julius is a frog. It is impossible that Brian is green. There is little chance that Winona is a mouse. There is little chance that if either 'Brian is green' or 'Julius is a frog' but not both then Greg is a swan. There is almost no chance that if 'Julius is a frog and Brian is green' then Bernhard is a lion. It is highly likely that if 'Julius is a frog and Winona is a mouse' then Emily is a wolf.
It is impossible that either 'Bernhard is a lion' or 'Brian is green' but not both.
It is impossible that either 'Bernhard is a lion' or 'Brian is green' but not both.
It is likely that either 'Bernhard is a lion' or 'Brian is green' 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
  0.2::factA.
  0.0::factB.
  0.1::factC.
  %hop1
  0.1::factX:-xor(factB,factA).
  0.02::factY:-and(factA,factB).
  0.9::factZ:-and(factA,factC).

  %hop2
  conclusion:-xor(factY,factB).

  query(conclusion).
  
Either 'Bernhard is a lion' or 'Brian is green' but not both.