%
% Standard operations from linear algebra.
%
+\ifx\havemjolinearalgebra\undefined
+\def\havemjolinearalgebra{1}
-% Needed for \lvert, \rVert, etc. and \operatorname.
-\usepackage{amsmath}
-% Wasysym contains the \ocircle that we use in \directsumperp.
-\usepackage{wasysym}
+\ifx\lvert\undefined
+ \usepackage{amsmath} % \lvert, \rVert, etc. and \operatorname.
+\fi
-% Part of the adjustbox package; needed to clip the \perp sign.
-\usepackage{trimclip}
+\ifx\ocircle\undefined
+ \usepackage{wasysym}
+\fi
+
+\ifx\clipbox\undefined
+ % Part of the adjustbox package; needed to clip the \perp sign.
+ \usepackage{trimclip}
+\fi
\input{mjo-common}
% The trace of an operator.
\newcommand*{\trace}[1]{ \operatorname{trace}\of{{#1}} }
+
+% The "rank" of its argument, which is context-dependent. It can mean
+% any or all of,
+%
+% * the rank of a matrix,
+% * the rank of a power-associative algebra (particularly an EJA),
+% * the rank of an element in a Euclidean Jordan algebra.
+%
+\newcommand*{\rank}[1]{ \operatorname{rank}\of{{#1}} }
+
+
% The ``span of'' operator. The name \span is already taken.
\newcommand*{\spanof}[1]{ \operatorname{span}\of{{#1}} }
% Now declare an orthogonal direct sum in terms of \oplusperp.
\newcommand*{\directsumperp}[2]{ {#1}\oplusperp{#2} }
+
+
+\fi