context: It is highly unlikely that Lily is a rhino. It is probably not the case that Bernhard is gray. It is probably the case that Greg is yellow.
hypothesis: We doubt that 'Bernhard is gray and Greg is yellow'.
valid_hypothesis: We doubt that 'Bernhard is gray and Greg is yellow'.
invalid_hypothesis: It is probably the case that 'Bernhard is gray and Greg is yellow'.
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
    0.05::factA.
    0.25::factB.
    0.7::factC.
    
  
    %hop2
    conclusion:-and(factB,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Bernhard is gray and Greg is yellow'.