context: It is highly unlikely that Mary is in the school. It is unlikely that Brian is a swan. It is probably the case that Bernhard is a frog.
hypothesis: There is almost no chance that 'Mary is in the school and Brian is a swan'.
valid_hypothesis: There is almost no chance that 'Mary is in the school and Brian is a swan'.
invalid_hypothesis: There is a better than even chance that 'Mary is in the school and Brian 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
    0.05::factA.
    0.2::factB.
    0.7::factC.
    
  
    %hop2
    conclusion:-and(factA,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary is in the school and Brian is a swan'.