context: It is probable that Jeff went to the bedroom. There is a very good chance that Yann is thirsty. It is unlikely that John put down the milk. It is highly likely that if 'John put down the milk and Yann is thirsty' then Julius is white. We doubt that if 'John put down the milk' or 'Yann is thirsty' or both then Brian is green. It is unlikely that if either 'Jeff went to the bedroom' or 'John put down the milk' but not both then Lily is a lion.
hypothesis: Chances are slight that 'Brian is green and Jeff went to the bedroom'.
valid_hypothesis: Chances are slight that 'Brian is green and Jeff went to the bedroom'.
invalid_hypothesis: We believe that 'Brian is green and Jeff went to the bedroom'.
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
    0.7::factA.
    0.8::factB.
    0.2::factC.
    %hop1
    0.9::factX:-and(factC,factB).
    0.2::factY:-or(factC,factB).
    0.2::factZ:-xor(factA,factC).
  
    %hop2
    conclusion:-and(factY,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is green and Jeff went to the bedroom'.