context: It is certain that John left the apple. It is highly likely that Mary went to the kitchen. It is unlikely that Sandra dropped the milk.
hypothesis: We doubt that 'John left the apple' or 'Sandra dropped the milk' or both.
valid_hypothesis: It is certain that 'John left the apple' or 'Sandra dropped the milk' or both.
invalid_hypothesis: We doubt that 'John left the apple' or 'Sandra dropped the milk' or 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
    1.0::factA.
    0.9::factB.
    0.2::factC.
    
  
    %hop2
    conclusion:-or(factA,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'John left the apple' or 'Sandra dropped the milk' or both.