\begin{definition}[Definition:Integer Reciprocal Space]
Let $\struct {\R, \tau_d}$ be the real number line $\R$ under the usual (Euclidean) topology $\tau_d$.
Let $A \subseteq \R$ be the set of all points on $\R$ defined as:
:$A := \set {\dfrac 1 n : n \in \Z_{>0} }$
That is:
:$A := \set {1, \dfrac 1 2, \dfrac 1 3, \dfrac 1 4, \ldots}$
Then $\struct {A, \tau_d}$ is the '''integer reciprocal space'''.
\end{definition}