context: It is improbable that Winona is a wolf. It is improbable that Lily is a frog. It is certain that John went to the garden.
hypothesis: It is highly likely that either 'Lily is a frog' or 'John went to the garden' but not both.
valid_hypothesis: It is highly likely that either 'Lily is a frog' or 'John went to the garden' but not both.
invalid_hypothesis: There is almost no chance that either 'Lily is a frog' or 'John went to the garden' but not both.
problog: 
    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.
    0.1::factB.
    1.0::factC.
    
  
    %hop2
    conclusion:-xor(factB,factC).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Lily is a frog' or 'John went to the garden' but not both.