Drop unused journal name macros from my BibTeX style.

[mjotex.git] / mjo-linear_algebra.tex

diff --git a/mjo-linear_algebra.tex b/mjo-linear_algebra.tex
index 9e32d2179a25e1d061eeeb1f063ed14bcdf36284..02e1d12aba4d6383ee2b79f44eea272d96457329 100644 (file)
--- a/mjo-linear_algebra.tex
+++ b/mjo-linear_algebra.tex
@@ -5,46 +5,64 @@
 % Needed for \lvert, \rVert, etc. and \operatorname.
 \usepackage{amsmath}
 
+% Wasysym contains the \ocircle that we use in \directsumperp.
+\usepackage{wasysym}
+
+% Part of the adjustbox package; needed to clip the \perp sign.
+\usepackage{trimclip}
+
 \input{mjo-common}
 
-% Absolute value (modulis) of a scalar.
-\newcommand*{\abs}[1]{ \left\lvert {#1} \right\rvert }
+% Absolute value (modulus) of a scalar.
+\newcommand*{\abs}[1]{\left\lvert{#1}\right\rvert}
 
 % Norm of a vector.
-\newcommand*{\norm}[1]{ \left\lVert {#1} \right\rVert }
+\newcommand*{\norm}[1]{\left\lVert{#1}\right\rVert}
 
 % The inner product between its two arguments.
-\newcommand*{\ip}[2]{ \langle {#1}, {#2} \rangle }
+\newcommand*{\ip}[2]{\left\langle{#1},{#2}\right\rangle}
 
 % The tensor product of its two arguments.
-\newcommand*{\tp}[2]{ {#1} \otimes {#2} }
+\newcommand*{\tp}[2]{ {#1}\otimes{#2} }
+
+% The Kronecker product of its two arguments. The usual notation for
+% this is the same as the tensor product notation used for \tp, but
+% that leads to confusion because the two definitions may not agree.
+\newcommand*{\kp}[2]{ {#1}\odot{#2} }
+
+% The adjoint of a linear operator.
+\newcommand*{\adjoint}[1]{ #1^{*} }
+
+% The ``transpose'' of a linear operator; namely, the adjoint, but
+% specialized to real matrices.
+\newcommand*{\transpose}[1]{ #1^{T} }
+
+% The trace of an operator.
+\newcommand*{\trace}[1]{ \operatorname{trace}\of{{#1}} }
 
 % The ``span of'' operator. The name \span is already taken.
-\newcommand*{\spanof}[1]{ \operatorname{span} \of{{#1}} }
+\newcommand*{\spanof}[1]{ \operatorname{span}\of{{#1}} }
 
 % The ``co-dimension of'' operator.
 \newcommand*{\codim}{ \operatorname{codim} }
 
-% The trace of an operator.
-\newcommand*{\trace}[1]{ \operatorname{trace} \of{{#1}} }
-
 % The orthogonal projection of its second argument onto the first.
 \newcommand*{\proj}[2] { \operatorname{proj}\of{#1, #2} }
 
 % The ``Automorphism group of'' operator.
-\newcommand*{\Aut}[1]{ \operatorname{Aut} \of{{#1}} }
+\newcommand*{\Aut}[1]{ \operatorname{Aut}\of{{#1}} }
 
 % The ``Lie algebra of'' operator.
-\newcommand*{\Lie}[1]{ \operatorname{Lie} \of{{#1}} }
+\newcommand*{\Lie}[1]{ \operatorname{Lie}\of{{#1}} }
 
 % The ``write a matrix as a big vector'' operator.
-\newcommand*{\vectorize}[1]{ \operatorname{vec} \of{{#1}} }
+\newcommand*{\vectorize}[1]{ \operatorname{vec}\of{{#1}} }
 
 % The ``write a big vector as a matrix'' operator.
-\newcommand*{\matricize}[1]{ \operatorname{mat} \of{{#1}} }
+\newcommand*{\matricize}[1]{ \operatorname{mat}\of{{#1}} }
 
 % An inline column vector, with parentheses and a transpose operator.
-\newcommand*{\colvec}[1]{ \left( {#1} \right)^{T} }
+\newcommand*{\colvec}[1]{ \left({#1}\right)^{T} }
 
 % Bounded linear operators on some space. The required argument is the
 % domain of those operators, and the optional argument is the
@@ -59,3 +77,21 @@
     \fi
   }
 }
+
+
+%
+% Orthogonal direct sum.
+%
+% First declare my ``perp in a circle'' operator, which is meant to be
+% like an \obot or an \operp except has the correct weight circle. It's
+% achieved by overlaying an \ocircle with a \perp, but only after we
+% clip off the top half of the \perp sign and shift it up.
+\DeclareMathOperator{\oplusperp}{\mathbin{
+  \ooalign{
+    $\ocircle$\cr
+    \raisebox{0.625\height}{$\clipbox{0pt 0pt 0pt 0.5\height}{$\perp$}$}\cr
+  }
+}}
+
+% Now declare an orthogonal direct sum in terms of \oplusperp.
+\newcommand*{\directsumperp}[2]{ {#1}\oplusperp{#2} }