\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} }