19 citations · 19 across the 1 of their papers we have counts for
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Lectures on Mathematical Cosmology
H. -J. Schmidt
We present mathematical details of several cosmological models, whereby the topological and the geometrical background will be emphasized.
On the Space of 3-dimensional Homogeneous Riemannian Manifolds
H. -J. Schmidt
We answer the following question: Let l, m, n be arbitrary real numbers. Does there exist a 3-dimensional homogeneous Riemannian manifold whose eigenvalues of the Ricci tensor are…
On space-times which cannot be distinguished by curvature invariants
H. -J. Schmidt
We present an example that non-isometric space-times with non-vanishing curvature scalar cannot be distinguished by curvature invariants.
The metric in the superspace of Riemannian metrics and its relation to gravity
H. -J. Schmidt
The space of all Riemannian metrics is infinite-dimensional. Nevertheless a great deal of usual Riemannian geometry can be carried over. The superspace of all Riemannian metrics sh…
Cosmic strings and strings in gravitational waves
H. -J. Schmidt, U. Semmelmann
We consider strings with the Nambu action as extremal surfaces in a given space-time, thus, we ignore their back reaction. Especially, we look for strings sharing one symmetry with…
The Newtonian limit of fourth-order gravity
H. -J. Schmidt
The weak-field slow-motion limit of fourth-order gravity will be discussed.