You may not have heard the names " Banksy" and "Poster Boy," but if you live in the Lower East Side or Dumbo chances are you've seen their work.

They are graffiti artists who are at war with one another. Just look at some of their works in the photos.

"Poster Boy" is currently in jail, but word is one of his people tagged over Banksy's work of a young boy sitting on a crate. And Banksy's "graf" of "I Love NY" was written over as well allegedly by the same rival.

However, we spoke to sociologist and author of the book "Graffiti NYC," Hugo Martinez, who is also an art dealer. He says these guys are not even legitimate graffiti artists and that they are working class artists looking for media attention, by creating the impression of a graffiti war that doesn't exist.

In fact, Hugo says the legitimate artists see it as sport, friendly competition and even a badge of honor if an artist they respect "disses" or "rags" their work.

You can see some examples from his Martinez Gallery website.