context: It is unlikely that Lily is a rhino. There is a very good chance that Sumit is thirsty. There is a very good chance that Greg is green. It is highly likely that if either 'Greg is green' or 'Lily is a rhino' but not both then Bernhard is a frog. It is likely that if either 'Greg is green' or 'Lily is a rhino' but not both then Fred put down the apple. We believe that if either 'Greg is green' or 'Lily is a rhino' but not both then John went to the hallway.
hypothesis: It is probably not the case that either 'Bernhard is a frog' or 'Greg is green' but not both.
valid_hypothesis: It is probably not the case that either 'Bernhard is a frog' or 'Greg is green' but not both.
invalid_hypothesis: It is certain that either 'Bernhard is a frog' or 'Greg is green' but not both.
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.
    0.8::factB.
    0.8::factC.
    %hop1
    0.9::factX:-xor(factC,factA).
    0.7::factY:-xor(factC,factA).
    0.75::factZ:-xor(factC,factA).
  
    %hop2
    conclusion:-xor(factX,factC).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Bernhard is a frog' or 'Greg is green' but not both.