Time travel

So, yesterday. Days of future past. Time travel. Wow. This might take a while. Here we go! There are many, many, many, many different time travel theories, I, am a geek, so I do have my own theories. I don't know the scientific name for them, but I do know them. The xmen used the most common, which is also the paradox one, my least favorite. I'm gonna call it the paradox. The paradox is basically you travel back, and whatever happens becomes the new reality. I'm calling it the paradox because you could go back, kill your grandma, you're moms never born, you aren't born, therefore you can't go back in time to kill your grandma. Since you can't kill you're grandma, she survives, has kids, her kid has you, you're there to go back and kill her. Paradox. The second theory, hanks theory, I'm going to call the river. The river theory is that even if you do something, the time stream course corrects itself. You kill you're grandma, a different person has your mom, your mom has you, everything's the same, but you have a different grandma. Then there's the alternate universe theory, where you go back in time, except you go to a different universe. You kill you grandma in that universe, and you've never excised in that universe, but you still can do that because you're grandma wasn't killed in your universe. Then there's my theory, it's all happened before (IAHB? I dunno what to call it!). In my theory, you can't go back to kill you're grandma. As a better example, you go back in time to say, stop someone from killing someone. But when you do, you cause person a to kill person b. You can't change time because that's how it happened originally. Um... You go back in time to stop World War II and talk hitler out of it, but what you say makes hitler feel like he should create the perfect world and start killing off Jews. You get it?
Books/movies/animes/videogames/tv shows that use each theory:
Paradox: X-Men: Days Of future past,
River: (I think) Doctor Who (I'm not sure), supernatural,
Alternate universe: DBZ
MY theory (can't find a name.....): Artemis Foul: The Time Paradox (A: I haven't finished it so I'm not sure, B: he used the real name for the theory), Harry Potter: The Prisoner Of Azkaban,
I KNOW I've seen more with time travel, and mostly the paradox, but my mind is totally blank now (at the start of the post I thought of like, five. Sorry!) I also know about some things that involve time travel, but I don't know the theory they use. LoZ: Ocarina of Time and LoZ: a link to the past...... So, if anyone knows, please tell me!
From da future
Super-chu
DeWitt
Raven


INVERTED PYRAMID!!!!!!!!!!!!!