context: Chances are slight that Bernhard is a rhino. It is impossible that Sandra took the football. There is a better than even chance that Greg is white. It is highly unlikely that if 'Greg is white and Sandra took the football' then Lily is gray. There is a better than even chance that if 'Bernhard is a rhino' or 'Sandra took the football' or both then Jessica is a cat. It is probably not the case that if either 'Sandra took the football' or 'Greg is white' but not both then Brian is a lion.
hypothesis: Chances are about even that 'Greg is white and Bernhard is a rhino'.
valid_hypothesis: It is highly unlikely that 'Greg is white and Bernhard is a rhino'.
invalid_hypothesis: Chances are about even that 'Greg is white and Bernhard is a rhino'.
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
    0.1::factA.
    0.0::factB.
    0.6::factC.
    %hop1
    0.05::factX:-and(factC,factB).
    0.6::factY:-or(factA,factB).
    0.25::factZ:-xor(factB,factC).
  
    %hop2
    conclusion:-and(factC,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Greg is white and Bernhard is a rhino'.