diff --git a/tex/iris.sty b/tex/iris.sty
index cce3a90a9bb42f5741125f4677777ba3576d5b41..2652092f4e94fff900dd9bb1b2f412d1ce185400 100644
--- a/tex/iris.sty
+++ b/tex/iris.sty
@@ -46,7 +46,7 @@
 \newcommand{\upclose}{\mathord{\uparrow}}
 \newcommand{\ALT}{\ |\ }
 
-\newcommand{\spac}{\hskip 0.2em plus 0.1em} % a space
+\newcommand{\spac}{\nobreak\hskip 0.2em plus 0.1em} % a space
 
 \def\All #1.{\forall #1.\spac}%
 \def\Exists #1.{\exists #1.\spac}%