context: It is probably not the case that Bernhard is green. There is little chance that Bill left the milk. It is likely that Julius is a rhino. It is probable that if 'Bill left the milk' or 'Julius is a rhino' or both then Lily is a lion. There is a better than even chance that if 'Julius is a rhino' or 'Bill left the milk' or both then John discarded the apple. It is unlikely that if 'Bill left the milk and Bernhard is green' then Brian is gray.
hypothesis: It is impossible that 'Bernhard is green and Brian is gray'.
valid_hypothesis: It is impossible that 'Bernhard is green and Brian is gray'.
invalid_hypothesis: It is likely that 'Bernhard is green and Brian is gray'.
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
    0.25::factA.
    0.1::factB.
    0.7::factC.
    %hop1
    0.7::factX:-or(factB,factC).
    0.6::factY:-or(factC,factB).
    0.2::factZ:-and(factB,factA).
  
    %hop2
    conclusion:-and(factA,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Bernhard is green and Brian is gray'.