It is improbable that Lily is a frog. It is almost certain that Julius is a frog. We believe that Bernhard is yellow. There is almost no chance that if 'Bernhard is yellow' or 'Julius is a frog' or both then Daniel took the football. It is probably the case that if 'Lily is a frog' or 'Julius is a frog' or both then John went to the kitchen. Chances are slight that if 'Lily is a frog' or 'Bernhard is yellow' or both then Greg is green.
It is highly likely that either 'Julius is a frog' or 'Lily is a frog' but not both.
It is highly likely that either 'Julius is a frog' or 'Lily is a frog' but not both.
It is impossible that either 'Julius is a frog' or 'Lily is a frog' 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.
  0.95::factB.
  0.75::factC.
  %hop1
  0.02::factX:-or(factC,factB).
  0.7::factY:-or(factA,factB).
  0.1::factZ:-or(factA,factC).

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

  query(conclusion).
  
Either 'Julius is a frog' or 'Lily is a frog' but not both.