context: There is almost no chance that Lily is a lion. We believe that Greg is a frog. It is certain that John took the apple. It is probably not the case that if either 'Greg is a frog' or 'John took the apple' but not both then Gertrude is a mouse. It is probably the case that if 'Lily is a lion and John took the apple' then Winona is a cat. It is certain that if 'John took the apple' or 'Greg is a frog' or both then Mary went to the garden.
hypothesis: We believe that 'John took the apple and Greg is a frog'.
valid_hypothesis: We believe that 'John took the apple and Greg is a frog'.
invalid_hypothesis: It is unlikely that 'John took the apple and Greg is a frog'.
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
    0.02::factA.
    0.75::factB.
    1.0::factC.
    %hop1
    0.25::factX:-xor(factB,factC).
    0.7::factY:-and(factA,factC).
    1.0::factZ:-or(factC,factB).
  
    %hop2
    conclusion:-and(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'John took the apple and Greg is a frog'.