move definition to concept

30_Thesis/sections/40_concept.tex

@@ -46,6 +46,14 @@ a users \emph{utility function} that maps a domain value to a utility value and
     \end{split}
 \end{equation}
 
+\subsection{Group Recommender}
+
+For a group recommender system additional definitions are needed. The attitude of a user is represented by their preferences $P$ which is directly related to the utility a user has from a domain value being present in the configuration. Let 
+\begin{gather} \label{tab:Foundations:GroupRecommenderSystem:Preferences}
+    P = \{ P_1, \dotsc, P_n\},\ \text{where} \\
+    P_i = \{(d,\ u_i(d)) \ | \ \forall d \in \mathfrak{D}(i),\ i=1,\dotsc,m \} \notag
+\end{gather}
+
 
 \section{Requirements}
 \label{sec:Concept:Requirements}