context: There is a very good chance that Julius is a rhino. It is almost certain that Brian is green. There is almost no chance that Mary got the football. It is certain that if either 'Mary got the football' or 'Julius is a rhino' but not both then Greg is white. There is a better than even chance that if either 'Julius is a rhino' or 'Mary got the football' but not both then Jeff went to the garden. We believe that if 'Mary got the football and Julius is a rhino' then Fred dropped the apple.
hypothesis: It is almost certain that 'Mary got the football and Julius is a rhino'.
valid_hypothesis: There is almost no chance that 'Mary got the football and Julius is a rhino'.
invalid_hypothesis: It is almost certain that 'Mary got the football and Julius is a rhino'.
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
    0.8::factA.
    0.95::factB.
    0.02::factC.
    %hop1
    1.0::factX:-xor(factC,factA).
    0.6::factY:-xor(factA,factC).
    0.75::factZ:-and(factC,factA).
  
    %hop2
    conclusion:-and(factC,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary got the football and Julius is a rhino'.