context: There is a very good chance that Greg is a swan. It is improbable that Julius is green. There is almost no chance that Sandra took the football.
hypothesis: Chances are slight that 'Julius is green and Greg is a swan'.
valid_hypothesis: Chances are slight that 'Julius is green and Greg is a swan'.
invalid_hypothesis: It is likely that 'Julius is green and Greg is a swan'.
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
    0.8::factA.
    0.1::factB.
    0.02::factC.
    
  
    %hop2
    conclusion:-and(factB,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Julius is green and Greg is a swan'.