There is almost no chance that Julius is a swan. It is certain that Bernhard is a frog. It is probable that John moved to the garden. It is highly likely that if 'Bernhard is a frog' or 'Julius is a swan' or both then Antoine is hungry. Chances are slight that if 'John moved to the garden and Bernhard is a frog' then Lily is white. It is impossible that if 'Bernhard is a frog and Julius is a swan' then Brian is gray.
It is probably not the case that either 'Bernhard is a frog' or 'John moved to the garden' but not both.
It is probably not the case that either 'Bernhard is a frog' or 'John moved to the garden' but not both.
It is probable that either 'Bernhard is a frog' or 'John moved to the garden' 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
  0.02::factA.
  1.0::factB.
  0.7::factC.
  %hop1
  0.9::factX:-or(factB,factA).
  0.1::factY:-and(factC,factB).
  0.0::factZ:-and(factB,factA).

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

  query(conclusion).
  
Either 'Bernhard is a frog' or 'John moved to the garden' but not both.