$λ$-ring structure in differential K-theory
Bo Liu, Xiaonan Ma
TL;DR
This work proves a splitting principle for differential K-theory and shows that the differential $K^0$-ring of a closed manifold carries a natural $\lambda$-ring structure. It then provides a constructive realization of Adams operations in differential K-theory, compatible with both the curvature map and the underlying Chern character, and extends these results to a $T_g$-equivariant setting for compact Lie group actions. The framework unifies algebraic $\lambda$-ring techniques with differential refinements, enabling explicit exterior powers and Adams operations in differential contexts. Overall, the results deliver a concrete differential-operator realization of classical $\lambda$-ring machinery with equivariant generalizations.
Abstract
We establish the splitting principle for differential K-theory, a refinement of topological K-theory that incorporates geometric data via differential forms. Using this principle, we prove that the differential $K^0$-ring associated to closed smooth manifolds admits a $λ$-ring structure. This structure enables a concrete construction of the Adams operations in differential K-theory introduced by Bunke. At last, we extend all these results to an equivariant setting associated with a compact Lie group action.
