context: It is probably the case that Brian is a lion. It is certain that Fred went to the garden. We doubt that Jessica is a wolf.
hypothesis: There is a very good chance that either 'Jessica is a wolf' or 'Fred went to the garden' but not both.
valid_hypothesis: There is a very good chance that either 'Jessica is a wolf' or 'Fred went to the garden' but not both.
invalid_hypothesis: It is highly unlikely that either 'Jessica is a wolf' or 'Fred 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
    0.7::factA.
    1.0::factB.
    0.2::factC.
    
  
    %hop2
    conclusion:-xor(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Jessica is a wolf' or 'Fred went to the garden' but not both.