The Poisson summation formula says that for a Schwartz function $f : \mathbf R^d \to \mathbf R$ and its Fourier transform $\widehat f$, we have $$\sum_{n \in \mathbf Z^d} f(x) = \sum_{n \in \mathbf Z^d} \widehat f(x).$$ Can this formula be explained conceptually along the lines of the following:
- we have a short exact sequence of groups $$0 \to \mathbf Z^d \to \mathbf R^d \stackrel \pi \to (\mathbf R/\mathbf Z)^d \to 0,$$
- the Pontryagin duals of these groups is the "same" exact sequence, but with arrows reversed.
- some sort of functoriality of Pontryagin duality.
Thanks!