context: It is highly unlikely that Greg is a rhino. Chances are about even that John left the football. We believe that Mary went to the hallway. We believe that if 'Greg is a rhino and John left the football' then Sandra got the football. It is highly unlikely that if 'Greg is a rhino and John left the football' then Jessica is a cat. It is unlikely that if 'Greg is a rhino' or 'Mary went to the hallway' or both then Bernhard is a lion.
hypothesis: It is impossible that 'Sandra got the football and Jessica is a cat'.
valid_hypothesis: It is impossible that 'Sandra got the football and Jessica is a cat'.
invalid_hypothesis: It is almost certain that 'Sandra got the football 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
    0.05::factA.
    0.5::factB.
    0.75::factC.
    %hop1
    0.75::factX:-and(factA,factB).
    0.05::factY:-and(factA,factB).
    0.2::factZ:-or(factA,factC).
  
    %hop2
    conclusion:-and(factX,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Sandra got the football and Jessica is a cat'.