Star domain

A star domain is a subset $𝑆 \subseteq ℝ 𝑛$ of Real coördinate space such that there exists a point $𝑠 0 \in 𝑆$ where for any $𝑠 \in 𝑆$ the line from $𝑠$ to $𝑠 0$ lies completely in $𝑆$ . topology Every star domain is simply connected.