Smooth \(Sp(2,\mathbf R)\)-actions on the 4-sphere
The author constructs a one-to-one correspondence between the equivariant diffeomorphisms of smooth \(Sp(2,\mathbf R)\)-actions on standard 4-sphere without fixed points and the equivalence classes of certain pairs of \(\mathbf R\)-actions and maps defined on the circle subject to five conditions. This implies that there are infinitely many smooth \(Sp(2,\mathbf R)\)-actions on the sphere without fixed points up to equivariant diffeomorphism.
scientific article; zbMATH DE number 1044140