% Needed for \mathbb.
\usepackage{amsfonts}
-% Place the argument in matching left/right parntheses.
+% Needed for \bigtimes.
+\usepackage{mathtools}
+
+% Place the argument in matching left/right parentheses.
\providecommand*{\of}[1]{ \left({#1}\right) }
% Group terms using parentheses.
\mathbb{C}\if\detokenize{#1}\detokenize{1}{}\else^{#1}\fi
}
-% The space of symmetric n-by-n matrices.
+% The space of real symmetric n-by-n matrices.
\providecommand*{\Sn}[1][n]{
\mathcal{S}\if\detokenize{#1}\detokenize{1}{}\else^{#1}\fi
}
+% The space of complex Hermitian n-by-n matrices.
+\providecommand*{\Hn}[1][n]{
+ \mathcal{H}\if\detokenize{#1}\detokenize{1}{}\else^{#1}\fi
+}
+
%
% Basic set operations
%
{ {#1}_{#2}^{#3}{#4} }
}
-\providecommand*{\intersectmany}[3]{ \binopmany{\cap}{#1}{#2}{#3} }
-\providecommand*{\cartprodmany}[3]{ \binopmany{\times}{#1}{#2}{#3} }
-\providecommand*{\directsummany}[3]{ \binopmany{\oplus}{#1}{#2}{#3} }
-\providecommand*{\unionmany}[3]{ \binopmany{\cup}{#1}{#2}{#3} }
+\providecommand*{\intersectmany}[3]{ \binopmany{\bigcap}{#1}{#2}{#3} }
+\providecommand*{\cartprodmany}[3]{ \binopmany{\bigtimes}{#1}{#2}{#3} }
+\providecommand*{\directsummany}[3]{ \binopmany{\bigoplus}{#1}{#2}{#3} }
+\providecommand*{\unionmany}[3]{ \binopmany{\bigcup}{#1}{#2}{#3} }
+
+
+% The four standard (UNLESS YOU'RE FRENCH) types of intervals along
+% the real line.
+\providecommand*{\intervaloo}[2]{ \left({#1},{#2}\right) } % open-open
+\providecommand*{\intervaloc}[2]{ \left({#1},{#2}\right] } % open-closed
+\providecommand*{\intervalco}[2]{ \left[{#1},{#2}\right) } % closed-open
+\providecommand*{\intervalcc}[2]{ \left[{#1},{#2}\right] } % closed-closed