context: It is highly unlikely that Bernhard is a frog. There is almost no chance that Jeff went to the bedroom. It is probably not the case that Greg is green. There is a very good chance that if 'Bernhard is a frog and Greg is green' then Julius is a swan. It is improbable that if 'Greg is green and Jeff went to the bedroom' then John got the football. It is certain that if 'Bernhard is a frog and Greg is green' then Mary left the football.
hypothesis: We believe that 'Jeff went to the bedroom' or 'John got the football' or both.
valid_hypothesis: There is almost no chance that 'Jeff went to the bedroom' or 'John got the football' or both.
invalid_hypothesis: We believe that 'Jeff went to the bedroom' or 'John got the football' or both.
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
    0.05::factA.
    0.02::factB.
    0.25::factC.
    %hop1
    0.8::factX:-and(factA,factC).
    0.1::factY:-and(factC,factB).
    1.0::factZ:-and(factA,factC).
  
    %hop2
    conclusion:-or(factB,factY).
  
    query(conclusion).
    
hypothesis_assertion: 'Jeff went to the bedroom' or 'John got the football' or both.