Talk:Controllability Gramian

If this Gramian is nonsingular, we have controllability.

However, for observability, wikipedia says the condition is "if and only if".

One or the other seem to be wrong (or else, they are not stated as accurately as possible)...

-- Biscay 12:03, 23 August 2007 (UTC)[reply]

The condition is if and only if. I have corrected the text and used the "external link" as reference (since there, the iff is demonstrated)Pivs (talk) 21:58, 19 November 2012 (UTC)[reply]

I recently updated the definition of W_c to include the solution to the Sylvester equation. There is a discrepancy between the definition given in the lecture notes of Professor A. Manitius and the definitions in the books by Gene Franklin and Chi-Tsong Chen. I have changed the article to reflect the definitions in those two texts. Hazelnusse (talk) 02:28, 6 June 2013 (UTC)[reply]