context: It is likely that Mary went to the office. It is highly likely that Bernhard is yellow. It is probably not the case that Brian is a swan. It is impossible that if either 'Brian is a swan' or 'Bernhard is yellow' but not both then Emily is a wolf. Chances are about even that if 'Mary went to the office and Bernhard is yellow' then Lily is white. There is little chance that if either 'Brian is a swan' or 'Mary went to the office' but not both then Sandra got the football.
hypothesis: It is impossible that 'Bernhard is yellow and Emily is a wolf'.
valid_hypothesis: It is impossible that 'Bernhard is yellow and Emily is a wolf'.
invalid_hypothesis: There is a very good chance that 'Bernhard is yellow and Emily is a wolf'.
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.
    0.9::factB.
    0.25::factC.
    %hop1
    0.0::factX:-xor(factC,factB).
    0.5::factY:-and(factA,factB).
    0.1::factZ:-xor(factC,factA).
  
    %hop2
    conclusion:-and(factB,factX).
  
    query(conclusion).
    
hypothesis_assertion: 'Bernhard is yellow and Emily is a wolf'.