context: It is improbable that Lily is a frog. It is likely that Winona is a wolf. There is almost no chance that John grabbed the apple. It is highly likely that if either 'John grabbed the apple' or 'Winona is a wolf' but not both then Fred went to the garden. It is probably the case that if 'Lily is a frog' or 'Winona is a wolf' or both then Greg is a swan. It is probably the case that if either 'Winona is a wolf' or 'Lily is a frog' but not both then Julius is a rhino.
hypothesis: It is almost certain that 'Winona is a wolf and Greg is a swan'.
valid_hypothesis: Chances are about even that 'Winona is a wolf and Greg is a swan'.
invalid_hypothesis: It is almost certain that 'Winona is a wolf and Greg is a swan'.
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
    0.1::factA.
    0.7::factB.
    0.02::factC.
    %hop1
    0.9::factX:-xor(factC,factB).
    0.7::factY:-or(factA,factB).
    0.7::factZ:-xor(factB,factA).
  
    %hop2
    conclusion:-and(factB,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Winona is a wolf and Greg is a swan'.