In mathematics, the indicator vector or characteristic vector or incidence vector of a subset T of a set S is the vector xT:=(xs)s∈S{\displaystyle x_{T}:=(x_{s})_{s\in S}} such that xs=1{\displaystyle x_{s}=1} if s∈T{\displaystyle s\in T} and xs=0{\displaystyle x_{s}=0} if s∉T.{\displaystyle s\notin T.}
