context: We doubt that Julius is a frog. It is impossible that Brian is green. There is little chance that John went to the bedroom. We believe that if either 'John went to the bedroom' or 'Julius is a frog' but not both then Sandra left the apple. It is likely that if 'John went to the bedroom and Julius is a frog' then Greg is a swan. There is little chance that if 'John went to the bedroom' or 'Brian is green' or both then Bernhard is green.
hypothesis: It is impossible that 'Sandra left the apple and Bernhard is green'.
valid_hypothesis: It is impossible that 'Sandra left the apple and Bernhard is green'.
invalid_hypothesis: It is probably the case that 'Sandra left the apple and Bernhard is green'.
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
    0.2::factA.
    0.0::factB.
    0.1::factC.
    %hop1
    0.75::factX:-xor(factC,factA).
    0.7::factY:-and(factC,factA).
    0.1::factZ:-or(factC,factB).
  
    %hop2
    conclusion:-and(factX,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Sandra left the apple and Bernhard is green'.