diff --git a/src/include/PTheory.h b/src/include/PTheory.h
index 7793fce5a..3c5b98ae9 100644
--- a/src/include/PTheory.h
+++ b/src/include/PTheory.h
@@ -383,7 +383,7 @@ class PTheory
      *
      * @param msrInfo Pointer to MSR file handler
      * @param runNo Run number for this theory (0-based)
-     * @param hasParent True if this is a sub-theory (for +/* operators)
+     * @param hasParent True if this is a sub-theory (for + / * operators)
      */
     PTheory(PMsrHandler *msrInfo, UInt_t runNo, const Bool_t hasParent = false);