\chapter{Foundations} \label{ch:Foundations} \section{Group Decision-Making} \label{sec:Foundation:GroupDecisionMaking} \section{Decision Tasks} \label{sec:Foundation:DecisionTask} \section{Recommender System} \label{sec:Foundation:RecommenderSystem} \section{Single User Decision Scenario} \label{sec:Foundation:SingleUserDecisionScenario} \section{Group Decision Scenario} \label{sec:Foundation:GroupDecisionScenario} \section{Product Configuration} \label{sec:Foundation:ProductConfiguration} Product configuration is a process consisting of a series of decision tasks whereby a product is constructed of components which interact with each other. During a configuration process no new components are created their interplay and specification is defined beforehand \cite[~ p. 42-43]{sabinProductConfigurationFrameworksa1998}. Formally a configuration problem can be specified as a \emph{constraint satisfaction problem (CSP)} \cite{tsangFoundationsConstraintSatisfaction1993} as \[ CSP(V,D,C) \] where \( V = \{v_1,\dots, v_n\} \) is a set of variables, \( D = dom : V \mapsto X \) is a relation of variables and their corresponding domain definitions \( X \), and \( C = C_{PREF} \cup C_{KB} \) is a set of constraints with customer preferences \( C_{PREF} \) and configuration knowledge base \( C_{KB} \) \cite{felfernigOpenConfiguration2014, felferningGroupBasedConfiguration2016}. \section{Collaborative Product Configuration} \label{sec:Foundation:CollaborativeProductConfiguration}