deterministic then what that means is that if I step through my mapping I should get back my original sample so if we think about the case of P of a be given a given of a would be this would map aid to his correspondence in B and then if you apply that again from the other direction B to a mapping you should get back a and this should hold you in both directions so this gives you another invariance so if you say that the relationship between these two distributions are indeed deterministic then I would say these