context: It is highly likely that Mary went to the kitchen. There is a better than even chance that Lily is a lion. It is almost certain that Greg is green. It is probable that if 'Lily is a lion and Mary went to the kitchen' then Brian is gray. Chances are slight that if 'Greg is green and Mary went to the kitchen' then Bernhard is a frog. There is almost no chance that if 'Greg is green and Mary went to the kitchen' then Sandra got the football.
hypothesis: It is impossible that 'Brian is gray and Sandra got the football'.
valid_hypothesis: It is impossible that 'Brian is gray and Sandra got the football'.
invalid_hypothesis: It is likely that 'Brian is gray and Sandra got 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
    0.9::factA.
    0.6::factB.
    0.95::factC.
    %hop1
    0.7::factX:-and(factB,factA).
    0.1::factY:-and(factC,factA).
    0.02::factZ:-and(factC,factA).
  
    %hop2
    conclusion:-and(factX,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is gray and Sandra got the football'.