diff -r e19cb4c11409 -r 299f6a8faccc src/HOL/SET_Protocol/document/root.tex
--- a/src/HOL/SET_Protocol/document/root.tex	Tue Mar 09 20:00:44 2021 +0100
+++ b/src/HOL/SET_Protocol/document/root.tex	Tue Mar 09 21:11:05 2021 +0100
@@ -1,4 +1,5 @@
 \documentclass[10pt,a4paper,twoside]{article}
+\usepackage[T1]{fontenc}
 \usepackage{graphicx}
 \usepackage{latexsym,theorem}
 \usepackage{isabelle,isabellesym}