--- a/lib/texinputs/isabellesym.sty Wed Jul 17 11:18:39 2019 +0200
+++ b/lib/texinputs/isabellesym.sty Wed Jul 17 16:10:05 2019 +0200
@@ -200,6 +200,8 @@
\newcommand{\isasymUpdown}{\isamath{\Updownarrow}}
\newcommand{\isasymlangle}{\isamath{\langle}}
\newcommand{\isasymrangle}{\isamath{\rangle}}
+\newcommand{\isasymllangle}{\isamath{\langle\mskip-5mu\langle}}
+\newcommand{\isasymrrangle}{\isamath{\rangle\mskip-5mu\rangle}}
\newcommand{\isasymlceil}{\isamath{\lceil}}
\newcommand{\isasymrceil}{\isamath{\rceil}}
\newcommand{\isasymlfloor}{\isamath{\lfloor}}