diff --git a/logic.sty b/logic.sty
index a2cafdf..441909d 100644
--- a/logic.sty
+++ b/logic.sty
@@ -129,6 +129,7 @@
 \DeclareSimpleMathOperator{CH}
 \DeclareSimpleMathOperator{DC}
 \DeclareSimpleMathOperator{Ord}
+\DeclareSimpleMathOperator{OR} % Ordinals
 \DeclareSimpleMathOperator{trcl}
 \DeclareSimpleMathOperator{tcl}
 \newcommand{\concat}{{}^\frown}
diff --git a/logic2.tex b/logic2.tex
index 871cebd..1a01e4e 100644
--- a/logic2.tex
+++ b/logic2.tex
@@ -33,6 +33,8 @@
 \input{inputs/lecture_07}
 \input{inputs/lecture_08}
 \input{inputs/lecture_09}
+% TODO \input{inputs/lecture_10}
+\input{inputs/lecture_11}
 
 
 \cleardoublepage