  Motivated by a result from string topology, we prove a duality in topological
Hochschild homology (THH). The duality relates the THH of an E_1-algebra
spectrum and the THH of its derived Koszul dual algebra under certain
compactness conditions. The result relies on results about module categories
which may be of interest on their own. Finally, we relate this result to
topological field theories and outline some future work.
