Add my work-in-progress \directsumperp.

[mjotex.git] / mjo-linear_algebra.tex

diff --git a/mjo-linear_algebra.tex b/mjo-linear_algebra.tex
index ebf4acddc359c7b02b6c9f81f29b05564a6290d8..5fce75a403b83ace1b686c622f05ea24e1248363 100644 (file)
--- a/mjo-linear_algebra.tex
+++ b/mjo-linear_algebra.tex
@@ -71,3 +71,19 @@
     \fi
   }
 }
+
+
+%
+% Orthogonal direct sum.
+%
+% Wasysym contains the \ocircle that we use in \directsumperp.
+\usepackage{wasysym}
+\usepackage{scalerel}
+\DeclareMathOperator{\oplusperp}{\mathbin{
+  \ooalign{
+    $\ocircle$\cr
+    \raisebox{\noexpand{0.65\height}}{${\vstretch{0.5}{\perp}}$}\cr
+  }
+}}
+
+\newcommand*{\directsumperp}[2]{ {#1}\oplusperp{#2} }