# setIndicator -- computes the signed indicator vector of an admissible set

## Synopsis

• Usage:
setIndicator(T,n)
• Inputs:
• Outputs:
• a list, corresponding to a vector in $\mathbb Z^n$

## Description

Let $S$ be a set consisting of elements $s$, where $s$ is either equal to $i$ or $i^*$ with $0 \leq i \leq n-1$. The set $S$ is said to be admissible if for any integer $i$, not both $i$ and $i^{*}$ are contained in $S$. This method produces the signed indicator vector of $S$. In particular, the setIndicator of $S$ is $\sum c_ie_i \in \mathbb Z^n$ where $c_i = 1$ if $i \in T$, $c_i = -1$ if $i^{*} \in T$ and $0$ otherwise.

 i1 : S1 = set{1,2,4,5}; i2 : S2 = set{1,"2*"}; i3 : setIndicator(S1,7) o3 = {0, 1, 1, 0, 1, 1, 0} o3 : List i4 : setIndicator(S2,3) o4 = {0, 1, -1} o4 : List

If the set is not admissible it produces an error.

 i1 : S3 = set{1,"1*","2*",3} o1 = set {1, 1*, 2*, 3} o1 : Set i2 : setIndicator(S3,4) stdio:2:1:(3): error: the signed subset is not admissible