context: It is almost certain that Brian is a rhino. It is highly likely that John went to the hallway. It is almost certain that Greg is yellow. It is almost certain that if 'Greg is yellow and Brian is a rhino' then Sandra left the milk. It is impossible that if 'John went to the hallway and Brian is a rhino' then Fred discarded the apple. It is probably the case that if either 'Greg is yellow' or 'Brian is a rhino' but not both then Julius is a frog.
hypothesis: It is almost certain that 'Fred discarded the apple and Julius is a frog'.
valid_hypothesis: It is impossible that 'Fred discarded the apple and Julius is a frog'.
invalid_hypothesis: It is almost certain that 'Fred discarded the apple and Julius is a frog'.
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
    0.95::factA.
    0.9::factB.
    0.95::factC.
    %hop1
    0.95::factX:-and(factC,factA).
    0.0::factY:-and(factB,factA).
    0.7::factZ:-xor(factC,factA).
  
    %hop2
    conclusion:-and(factY,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Fred discarded the apple and Julius is a frog'.