context: It is impossible that Greg is a frog. It is highly unlikely that Winona is a wolf. It is unlikely that Lily is a rhino. It is likely that if 'Lily is a rhino and Winona is a wolf' then Fred left the apple. There is almost no chance that if 'Winona is a wolf and Lily is a rhino' then Brian is yellow. It is certain that if either 'Lily is a rhino' or 'Winona is a wolf' but not both then Mary went to the garden.
hypothesis: There is a very good chance that 'Greg is a frog' or 'Winona is a wolf' or both.
valid_hypothesis: It is highly unlikely that 'Greg is a frog' or 'Winona is a wolf' or both.
invalid_hypothesis: There is a very good chance that 'Greg is a frog' or 'Winona is a wolf' 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
    0.0::factA.
    0.05::factB.
    0.2::factC.
    %hop1
    0.7::factX:-and(factC,factB).
    0.02::factY:-and(factB,factC).
    1.0::factZ:-xor(factC,factB).
  
    %hop2
    conclusion:-or(factA,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Greg is a frog' or 'Winona is a wolf' or both.