Hey all. I am currently reading an article and there is a paragraph that I am having a hard time understand. This is what the paragraph says: "Since Ar = Arτ and Ai = -Aiτ, we know that only the lower triangular (including the diagonal) elements of Ar are independent and only the strictly lower triangular (excluding the diagonal) elements of Ai are independent." I don't exactly know what "independent elements" means in this case. Are we talking about algebraic independence (because linear independence makes no sense to me in this case)? If yes, can someone please provide some insight into how it applies in this case? I read about algebraic independence on wiki, so I do have a general picture of what it is. If you would like to refer to the article, here it is: http://www.ee.ucr.edu/~yhua/MILCOM_2013_Reprint.pdf The paragraph is located under equation 9 of page 4 of the pdf. Thank you PF.