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