context: It is likely that Greg is yellow. Chances are slight that Mary went to the office. There is a very good chance that Bernhard is gray.
hypothesis: It is highly unlikely that 'Mary went to the office and Greg is yellow'.
valid_hypothesis: It is highly unlikely that 'Mary went to the office and Greg is yellow'.
invalid_hypothesis: There is a better than even chance that 'Mary went to the office 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
    0.7::factA.
    0.1::factB.
    0.8::factC.
    
  
    %hop2
    conclusion:-and(factB,factA).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary went to the office and Greg is yellow'.