mjo-linear_algebra.tex: update a comment before abusing notation.

I'm about to use \Hn to denote the Hermitian matrices over a general,
specified field. So first let's document that.

diff --git a/mjo-linear_algebra.tex b/mjo-linear_algebra.tex
index c57e9b9534309d70d760540ba464b94511a1f085..a534523765ef1fd20f7729af25836bb2075fcd3e 100644 (file)
--- a/mjo-linear_algebra.tex
+++ b/mjo-linear_algebra.tex
@@ -151,7 +151,9 @@
 
 % The space of complex Hermitian n-by-n matrices. Does not reduce to
 % merely "H" when n=1 since H^{n} does not mean an n-fold cartesian
-% product of H^{1}.
+% product of H^{1}. The field may also be given rather than assumed
+% to be complex; for example \Hn[3]\of{\mathbb{O}} might denote the
+% 3-by-3 Hermitian matrices with octonion entries.
 \newcommand*{\Hn}[1][n]{ \mathcal{H}^{#1} }
 \ifdefined\newglossaryentry
   \newglossaryentry{Hn}{