A sum formula for Casson's \(\lambda\)-invariant
The Casson-invariant of a class of homology-3-spheres is computed, which are obtained by glueing two knot-exteriors in homology-3-spheres along their torus-boundaries. This generalizes a result of \textit{C. Gordon} [Topology 14, 151-172 (1975; Zbl 0304.57003)] who did the same for the Rohlin-invariant, i.e., the mod 2-reduction of Casson's invariant.
scientific article; zbMATH DE number 4105876