Circular spacing ($\Vert {\theta }_r-{\theta }_s\Vert \ge \delta$)

Points ${\theta }_r$ have circular spacing at least $\delta$ when $\Vert {\theta }_r-{\theta }_s\Vert \ge \delta$ for distinct $r,s$, where $\Vert t\Vert ={\min }_{k\in \mathbb{Z}}|t-k|$. The distance is measured on the circle group $\mathbb{R}/\mathbb{Z}$, so points near zero and one can be close.