+\ifdefined\newglossaryentry
+ \newglossaryentry{C}{
+ name={\ensuremath{\Cn[1]}},
+ description={the field of complex numbers},
+ sort=C
+ }
+\fi
+
+
+% The space of real symmetric n-by-n matrices.
+\newcommand*{\Sn}[1][n]{
+ \mathcal{S}\if\detokenize{#1}\detokenize{1}{}\else^{#1}\fi
+}
+
+\ifdefined\newglossaryentry
+ \newglossaryentry{Sn}{
+ name={\ensuremath{\Sn}},
+ description={the set of $n$-by-$n$ real symmetric matrices},
+ sort=Sn
+ }
+\fi
+
+% The space of complex Hermitian n-by-n matrices.
+\newcommand*{\Hn}[1][n]{
+ \mathcal{H}\if\detokenize{#1}\detokenize{1}{}\else^{#1}\fi
+}
+
+\ifdefined\newglossaryentry
+ \newglossaryentry{Hn}{
+ name={\ensuremath{\Hn}},
+ description={the set of $n$-by-$n$ complex Hermitian matrices},
+ sort=Hn
+ }
+\fi