context: We doubt that Julius is a rhino. It is certain that Mary took the football. It is certain that Fred dropped the milk.
hypothesis: It is unlikely that 'Julius is a rhino and Mary took the football'.
valid_hypothesis: It is unlikely that 'Julius is a rhino and Mary took the football'.
invalid_hypothesis: We believe that 'Julius is a rhino and Mary took the football'.
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.
    1.0::factB.
    1.0::factC.
    
  
    %hop2
    conclusion:-and(factA,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Julius is a rhino and Mary took the football'.