\newcommand*{\abs}[1]{\left\lvert{#1}\right\rvert}
% Norm of a vector.
\newcommand*{\norm}[1]{\left\lVert{#1}\right\rVert}
% The inner product between its two arguments.
\newcommand*{\abs}[1]{\left\lvert{#1}\right\rvert}
% Norm of a vector.
\newcommand*{\norm}[1]{\left\lVert{#1}\right\rVert}
% The inner product between its two arguments.
% The ``span of'' operator. The name \span is already taken.
\newcommand*{\spanof}[1]{ \operatorname{span}\of{{#1}} }
% The ``co-dimension of'' operator.
\newcommand*{\codim}{ \operatorname{codim} }
% The ``span of'' operator. The name \span is already taken.
\newcommand*{\spanof}[1]{ \operatorname{span}\of{{#1}} }
% The ``co-dimension of'' operator.
\newcommand*{\codim}{ \operatorname{codim} }
% The orthogonal projection of its second argument onto the first.
\newcommand*{\proj}[2] { \operatorname{proj}\of{#1, #2} }
% The orthogonal projection of its second argument onto the first.
\newcommand*{\proj}[2] { \operatorname{proj}\of{#1, #2} }