context: There is a better than even chance that Fred left the football. We doubt that Greg is yellow. It is highly likely that Yann is hungry. It is highly unlikely that if 'Yann is hungry and Greg is yellow' then Bernhard is a rhino. It is likely that if 'Greg is yellow' or 'Yann is hungry' or both then Julius is a lion. It is probable that if either 'Greg is yellow' or 'Yann is hungry' but not both then Lily is green.
hypothesis: Chances are slight that 'Julius is a lion and Greg is yellow'.
valid_hypothesis: Chances are slight that 'Julius is a lion and Greg is yellow'.
invalid_hypothesis: It is probably the case that 'Julius is a lion and Greg is yellow'.
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
    0.6::factA.
    0.2::factB.
    0.9::factC.
    %hop1
    0.05::factX:-and(factC,factB).
    0.7::factY:-or(factB,factC).
    0.7::factZ:-xor(factB,factC).
  
    %hop2
    conclusion:-and(factY,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Julius is a lion and Greg is yellow'.