context: It is unlikely that John took the football. It is likely that Winona is a mouse. Chances are about even that Brian is yellow. It is probably not the case that if 'John took the football and Brian is yellow' then Jessica is a cat. We believe that if 'Winona is a mouse' or 'Brian is yellow' or both then Bernhard is a lion. It is unlikely that if either 'Winona is a mouse' or 'Brian is yellow' but not both then Lily is a swan.
hypothesis: Chances are about even that 'Brian is yellow and Bernhard is a lion'.
valid_hypothesis: Chances are about even that 'Brian is yellow and Bernhard is a lion'.
invalid_hypothesis: It is almost certain that 'Brian is yellow and Bernhard is a lion'.
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
    0.2::factA.
    0.7::factB.
    0.5::factC.
    %hop1
    0.25::factX:-and(factA,factC).
    0.75::factY:-or(factB,factC).
    0.2::factZ:-xor(factB,factC).
  
    %hop2
    conclusion:-and(factC,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Brian is yellow and Bernhard is a lion'.