diff --git a/main/background.tex b/main/background.tex
index f58b76a..8343ba8 100644
--- a/main/background.tex
+++ b/main/background.tex
@@ -186,7 +186,7 @@ Q^{\text{ab}}\dot{=}\begin{array}{c|ccccc}
 % \end{array}
 % \]
 
-Then,
+Then, 
 \[
 N^{\text{ab}}=(I_5-Q^{\text{ab}})^{-1}=\begin{array}{c|ccccc}
  & \text{A} & \text{B} & \text{C} & \text{D} & \text{E}  \\\hline