1 files changed, 18 insertions, 0 deletions
diff --git a/intro.tex b/intro.tex
index a196602..f8de19f 100644
--- a/intro.tex
+++ b/intro.tex
@@ -35,6 +35,24 @@
 }
 {\endMakeFramed}
 
+\makeatletter
+\newenvironment{sqcases}{%
+  \matrix@check\sqcases\env@sqcases
+}{%
+  \endarray\right.%
+}
+\def\env@sqcases{%
+  \let\@ifnextchar\new@ifnextchar
+  \left\lbrack
+  \def\arraystretch{1.2}%
+  \array{@{}l@{\quad}l@{}}%
+}
+\makeatother
+
+\DeclareRobustCommand{\divby}{%
+  \mathrel{\vbox{\baselineskip.65ex\lineskiplimit0pt\hbox{.}\hbox{.}\hbox{.}}}%
+}
+
 \newcommand{\question}[2]{
     \bigskip\bigskip
     \begin{cframed}