context: It is unlikely that Sandra dropped the milk. There is a very good chance that Mary took the football. Chances are about even that Lily is green.
hypothesis: It is highly unlikely that 'Sandra dropped the milk' or 'Mary took the football' or both.
valid_hypothesis: There is a very good chance that 'Sandra dropped the milk' or 'Mary took the football' or both.
invalid_hypothesis: It is highly unlikely that 'Sandra dropped the milk' or 'Mary took the football' 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
    0.2::factA.
    0.8::factB.
    0.5::factC.
    
  
    %hop2
    conclusion:-or(factA,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Sandra dropped the milk' or 'Mary took the football' or both.