context: Chances are slight that Mary went to the garden. There is almost no chance that Daniel dropped the apple. There is almost no chance that Lily is a swan.
hypothesis: Chances are slight that either 'Daniel dropped the apple' or 'Mary went to the garden' but not both.
valid_hypothesis: Chances are slight that either 'Daniel dropped the apple' or 'Mary went to the garden' but not both.
invalid_hypothesis: There is a very good chance that either 'Daniel dropped the apple' or 'Mary 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.
    0.02::factB.
    0.02::factC.
    
  
    %hop2
    conclusion:-xor(factB,factA).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Daniel dropped the apple' or 'Mary went to the garden' but not both.