# Examining a DocumentTermMatrix in RTextTools

I created a DocumentTermMatrix for text mining using RTextTools. The rows for this DocumentTermMatrix correspond to dataframe rows and matix columns correspond to words. My question is : How can I get the words (labels vector) for examining the DocumentTermMatrix ? In other words, How can I get the vector of these 904 words?

require(RTextTools,quietly=TRUE)
data(USCongress)

doc_matrix <- create_matrix(USCongress\$text, language="english",   removeNumbers=TRUE, stemWords=TRUE, removeSparseTerms=.998)

dim(USCongress)
[1] 4449    6

dim(doc_matrix)
[1] 4449  904


# turn into simple matrix