\'Etale duality for constructible sheaves on arithmetic schemes

In this note we relate three topics for arithmetic schemes: a general duality for 'etale constructible torsion sheaves, an 'etale homology theory, and a Gersten-Bloch-Ogus-Kato complex. The results in this paper have been used in other papers of the authors ([JS], [Sa], [SaH] in the list of references).