context: It is likely that Mary moved to the office. There is almost no chance that Sandra left the milk. It is improbable that Lily is yellow.
hypothesis: It is probable that either 'Sandra left the milk' or 'Mary moved to the office' but not both.
valid_hypothesis: It is probable that either 'Sandra left the milk' or 'Mary moved to the office' but not both.
invalid_hypothesis: It is highly unlikely that either 'Sandra left the milk' or 'Mary moved to the office' 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.
    0.02::factB.
    0.1::factC.
    
  
    %hop2
    conclusion:-xor(factB,factA).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Sandra left the milk' or 'Mary moved to the office' but not both.