--- a/lib/texinputs/isabelle.sty Wed Jul 17 11:18:39 2019 +0200
+++ b/lib/texinputs/isabelle.sty Wed Jul 17 16:10:05 2019 +0200
@@ -207,8 +207,6 @@
\def\isachartilde{\isamath{{}\sp{\sim}}}%
\def\isacharbackquoteopen{\isatext{\raise.3ex\hbox{$\scriptscriptstyle\langle$}}}%
\def\isacharbackquoteclose{\isatext{\raise.3ex\hbox{$\scriptscriptstyle\rangle$}}}%
-\def\isacharverbatimopen{\isamath{\langle\!\langle}}%
-\def\isacharverbatimclose{\isamath{\rangle\!\rangle}}%
}
\newcommand{\isabellestyleliteral}{%