Black Swan- Nina and her Mom

I read an article on the internet today. It was about the relationship between Nina and her mother in the film Black Swan. That article had an interesting theory I wanted to talk about. So, if you haven't seen that movie yet- see it. Spoilers ahead.
I really wanted to write more about this in my initial review, but there was so much to cover I kind of passed over it. I think Nina and her mother's relationship was pivotal to understanding the rest of the film. In this article I read, the author says that he thinks Nina's mom was sexually abusing her. When I saw the movie, that was not my reaction to their relationship. I admit it was weird, and there was possibly more going on than what the film showed. I thought that Nina's mom was simply a control freak. She was living out her failed dreams of a dancing career through her daughter, a thing many parents do. It was as if Nina's mom was keeping her like a toy ballerina, like one of those wind up ones. She wasn't letting Nina grow into her own person.
I do think the sexual abuse idea has weight. It would explain why Nina went bat shit insane over the course of the movie. It would explain why she didn't have any close relationships outside of her mother and why she seemed repulsed at the idea of sex. The movie doesn't really go into it, which I think is a good thing. The truth is, I liked that you really don't know the full nature of their relationship. It makes it that much creepier. You know that Nina's mom is a controlling force in her life, and yeah, there's probably more there, but that's not the focus of the movie. Nina's deteriorating mental state is. I did have an interesting theory of my own while watching the movie about those two. I wondered if Nina's mom never existed at all, or had died at some point earlier. Like in the movie Psycho, Nina may have been imagining her mom and trying to please her "ghost" by being a ballerina like her mom wanted to be. Is that crazy? Maybe, but you never see Nina's mom interact with anyone other than Nina. The only time she even goes out of the house is to her daughter's performance at the end WHERE SHE FUCKING DIES. So yeah, Nina's mom may have been in her head too. I'm really glad the movie doesn't attempt some explanation of this, because it would have become too convoluted if it did. It gives you enough to understand the plot, but doesn't spell everything out for you. One of the reasons I love this film so much is because of that, it's open for interpretation.