context: It is probably the case that Mary went to the garden. It is probably not the case that Daniel got the football. It is unlikely that Gertrude is a cat.
hypothesis: It is probably not the case that either 'Gertrude is a cat' or 'Daniel got the football' but not both.
valid_hypothesis: It is probably not the case that either 'Gertrude is a cat' or 'Daniel got the football' but not both.
invalid_hypothesis: It is probable that either 'Gertrude is a cat' or 'Daniel got the football' 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.
    0.25::factB.
    0.2::factC.
    
  
    %hop2
    conclusion:-xor(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Gertrude is a cat' or 'Daniel got the football' but not both.