context: There is a very good chance that Greg is a frog. Chances are slight that Gertrude is a cat. It is likely that Brian is a swan. It is unlikely that if 'Gertrude is a cat and Brian is a swan' then Sandra dropped the milk. It is improbable that if 'Gertrude is a cat and Greg is a frog' then John went to the garden. It is highly unlikely that if 'Brian is a swan' or 'Greg is a frog' or both then Jessica is a cat.
hypothesis: It is highly unlikely that 'Greg is a frog and Jessica is a cat'.
valid_hypothesis: It is highly unlikely that 'Greg is a frog and Jessica is a cat'.
invalid_hypothesis: It is highly likely that 'Greg is a frog and Jessica is a cat'.
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:-and(factB,factC).
    0.1::factY:-and(factB,factA).
    0.05::factZ:-or(factC,factA).
  
    %hop2
    conclusion:-and(factA,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Greg is a frog and Jessica is a cat'.