context: It is unlikely that Greg is a frog. It is impossible that John left the football. There is almost no chance that Winona is a mouse. We believe that if 'Greg is a frog' or 'John left the football' or both then Brian is a rhino. There is a very good chance that if 'John left the football and Winona is a mouse' then Lily is green. It is likely that if 'Winona is a mouse and Greg is a frog' then Sandra grabbed the milk.
hypothesis: It is impossible that 'John left the football and Winona is a mouse'.
valid_hypothesis: It is impossible that 'John left the football and Winona is a mouse'.
invalid_hypothesis: It is likely that 'John left the football and Winona is a mouse'.
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.
    0.02::factC.
    %hop1
    0.75::factX:-or(factA,factB).
    0.8::factY:-and(factB,factC).
    0.7::factZ:-and(factC,factA).
  
    %hop2
    conclusion:-and(factB,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'John left the football and Winona is a mouse'.