Parity check matrices

Professor Paul Rubin has pointed out an error in my earlier post on on parity check matrices contains a fairly big error (and I have since spotted a less serious one) – so it is in need to rewriting or serious editing.

To make sure I got it right next time I bought a book – Information and Coding Theory (Springer Undergraduate Mathematics Series) – and it seems pretty good.

A rewrite or new post will follow in due course.