context: It is certain that Greg is a frog. Chances are slight that Mary went to the garden. There is a very good chance that John moved to the office.
hypothesis: We believe that 'John moved to the office and Mary went to the garden'.
valid_hypothesis: It is improbable that 'John moved to the office and Mary went to the garden'.
invalid_hypothesis: We believe that 'John moved to the office and Mary went to the garden'.
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
    1.0::factA.
    0.1::factB.
    0.8::factC.
    
  
    %hop2
    conclusion:-and(factC,factB).
  
    query(conclusion).
    
hypothesis_assertion: 'John moved to the office and Mary went to the garden'.