context: There is a better than even chance that Bernhard is gray. It is certain that Brian is a swan. It is almost certain that Bill went to the garden. It is probably not the case that if either 'Brian is a swan' or 'Bill went to the garden' but not both then Jason is bored. We believe that if either 'Brian is a swan' or 'Bernhard is gray' but not both then Julius is a frog. It is highly unlikely that if 'Bernhard is gray' or 'Brian is a swan' or both then Greg is yellow.
hypothesis: It is almost certain that 'Bill went to the garden and Brian is a swan'.
valid_hypothesis: It is almost certain that 'Bill went to the garden and Brian is a swan'.
invalid_hypothesis: It is probably not the case that 'Bill went to the garden and Brian 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
    0.6::factA.
    1.0::factB.
    0.95::factC.
    %hop1
    0.25::factX:-xor(factB,factC).
    0.75::factY:-xor(factB,factA).
    0.05::factZ:-or(factA,factB).
  
    %hop2
    conclusion:-and(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'Bill went to the garden and Brian is a swan'.