3 papers
math.DG2026
Differential Invariants of Carrollian Spacetimes
Boris Kruglikov, Eivind Schneider, Wijnand Steneker
We compute invariants of Carrollian spacetimes, deriving them from the geometry of the screen bundle. For generic Carrollian structures we specify how to generate the entire algebr…
math.DG2026
On globally invariant Euler--Lagrange equations for curves
Boris Kruglikov, Eivind Schneider, Wijnand Steneker
Invariant Lagrangians yield invariant Euler-Lagrange equations, and it was discussed in the literature how to compute those using various local methods. The focus of this paper is…
math.DG2025
Invariant divisors and equivariant line bundles
Boris Kruglikov, Eivind Schneider
Scalar relative invariants play an important role in the theory of group actions on a manifold as their zero sets are invariant hypersurfaces. Relative invariants are central in ma…