context: It is probable that Mary went to the hallway. There is almost no chance that Greg is yellow. We believe that Julius is a swan. It is certain that if 'Greg is yellow and Mary went to the hallway' then Brian is a rhino. It is probably the case that if 'Julius is a swan' or 'Mary went to the hallway' or both then John left the milk. There is little chance that if 'Greg is yellow' or 'Mary went to the hallway' or both then Lily is a lion.
hypothesis: It is almost certain that 'Brian is a rhino and Greg is yellow'.
valid_hypothesis: There is almost no chance that 'Brian is a rhino and Greg is yellow'.
invalid_hypothesis: It is almost certain that 'Brian is a rhino and Greg is yellow'.
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.
    0.02::factB.
    0.75::factC.
    %hop1
    1.0::factX:-and(factB,factA).
    0.7::factY:-or(factC,factA).
    0.1::factZ:-or(factB,factA).
  
    %hop2
    conclusion:-and(factX,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is a rhino and Greg is yellow'.