diff --git a/30_Thesis/sections/40_concept.tex b/30_Thesis/sections/40_concept.tex
index 90a9151..377cb10 100644
--- a/30_Thesis/sections/40_concept.tex
+++ b/30_Thesis/sections/40_concept.tex
@@ -40,9 +40,10 @@ Instead of a single person configuring a product, a group of people is configuri
 and a user's \emph{utility function} that maps a domain value to a utility value and is only known to the user
 \begin{equation}
     \begin{split}
-        u_i(d_j), \qquad \text{where}\ & d_j \in  \mathfrak{D}(j),\\
+        u_i(d_j), \qquad \text{where}\ & u_i(d_j) \in [0,1] \\
+        & d_j \in  \mathfrak{D}(j),\\
         & 1 <= j <= m, \\
-        & 1 <= i <= n .
+        & 1 <= i <= n.
     \end{split}
 \end{equation}