The string coproduct “knows”Reidemeister/Whitehead torsion

The string coproduct "knows" Reidemeister/Whitehead torsion FLORIAN NAEFWe show that the string coproduct is not homotopy invariant.More precisely, we show that the (reduced) coproducts are different on L.1; 7/ and L.2; 7/.Moreover, the coproduct on L.k; 7/ can be expressed in terms of the Reidemeister torsion and hence transforms with respect to the Whitehead torsion of a homotopy equivalence.The string coproduct can thereby be used to compute the image of the Whitehead torsion under the Dennis trace map.55P50