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• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeAug 27th 2014
• (edited Aug 27th 2014)

I gave Pontryagin duality for torsion abelian groups its own entry, cross-linked of course with the examples-section at Pontryagin dual and with all other relevant entries.

Mainly I wanted to record this diagram here in a way that one could link to it quasi-directly:

$\array{ &\mathbb{Z}[p^{-1}]/\mathbb{Z} &\hookrightarrow& \mathbb{Q}/\mathbb{Z} &\hookrightarrow& \mathbb{R}/\mathbb{Z} \\ {}^{\mathllap{hom(-,\mathbb{R}/\mathbb{Z})}}\downarrow \\ &\mathbb{Z}_p &\leftarrow& \hat \mathbb{Z} &\leftarrow& \mathbb{Z} }$