diff -r ab40ff2fdc67 -r 3f9d03571eaa lib/texinputs/isabelle.sty
--- 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}{%