Structure of the Riemann tensor in higher-dimensional Kerr-NUT-(A)dS spaces
This paper investigates the algebraic and differential structure of the Riemann tensor in higher-dimensional Kerr-NUT-(A)dS spaces to pursue an IDEAL characterization of these metrics, proving a no-go theorem that no non-trivial 2-form can be covariantly constructed from the undifferentiated Riemann tensor alone while successfully characterizing the family of valid curvature tensors through specific algebraic and differential conditions derived from the principal tensor's integrability and the Bianchi identity.