context: There is a very good chance that Mary got the football. Chances are slight that Greg is a rhino. It is likely that Sandra dropped the apple. It is unlikely that if either 'Mary got the football' or 'Greg is a rhino' but not both then Bernhard is yellow. It is highly likely that if either 'Sandra dropped the apple' or 'Greg is a rhino' but not both then Lily is a frog. There is almost no chance that if either 'Mary got the football' or 'Greg is a rhino' but not both then Julius is gray.
hypothesis: Chances are slight that 'Mary got the football' or 'Lily is a frog' or both.
valid_hypothesis: It is highly likely that 'Mary got the football' or 'Lily is a frog' or both.
invalid_hypothesis: Chances are slight that 'Mary got the football' or 'Lily is a frog' 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
    0.8::factA.
    0.1::factB.
    0.7::factC.
    %hop1
    0.2::factX:-xor(factA,factB).
    0.9::factY:-xor(factC,factB).
    0.02::factZ:-xor(factA,factB).
  
    %hop2
    conclusion:-or(factA,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary got the football' or 'Lily is a frog' or both.