context: There is almost no chance that Sandra left the football. It is almost certain that Brian is a frog. We believe that Lily is gray.
hypothesis: It is probable that 'Lily is gray and Brian is a frog'.
valid_hypothesis: It is probable that 'Lily is gray and Brian is a frog'.
invalid_hypothesis: There is little chance that 'Lily is gray and Brian is a frog'.
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
    0.02::factA.
    0.95::factB.
    0.75::factC.
    
  
    %hop2
    conclusion:-and(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Lily is gray and Brian is a frog'.