Talk:Semi-orthogonal matrix

Semi-orthogonal includes orthogonal?
I suspect that the set of semi-orthogonal matrices includes the set of orthogonal matrices, but at least some references seem to be indicate otherwise. I wrote the article in its current form (where semi-orthogonal excludes orthogonal) partially out of the ease of not having to deal with the extra case of orthogonal. If semi-orthogonal should include orthogonal, please change the article accordingly. --Tekhnofiend (talk) 04:40, 18 January 2012 (UTC)

Use of norm in isometry property
I presume the vector p-norm is meant by the context. I think a footnote noting that $$\|\cdot\|_2$$ corresponds to the standard Euclidean norm in the case of a vector as in this case (or any more correct statement thereof) would be helpful to the many readers unfamiliar with this notation. — Quondum☏✎ 05:23, 10 February 2012 (UTC)