40 citations · 173 across the 14 of their papers we have counts for
12 papers · 1 filter
Influence of geometry variations on the gravitational focusing of timelike geodesic congruences
Masafumi Seriu
We derive a set of equations describing the linear response of the convergence properties of a geodesic congruence to arbitrary geometry variations. It is a combination of equation…
Dynamical Evolution of a Cylindrical Shell with Rotational Pressure
Masafumi Seriu
We prepare a general framework for analyzing the dynamics of a cylindrical shell in the spacetime with cylindrical symmetry. Based on the framework, we investigate a particular mod…
Evolution of the discrepancy between a universe and its model
Masafumi Seriu
We study a fundamental issue in cosmology: Whether we can rely on a cosmological model to understand the real history of the Universe. This fundamental, still unresolved issue is o…
Spectral Evolution of the Universe
Masafumi Seriu
We derive the evolution equations for the spectra of the Universe. Here "spectra" means the eigenvalues of the Laplacian defined on a space, which contain the geometrical informati…
Spectral Representation and the Averaging Problem in Cosmology
Masafumi Seriu
We investigate the averaging problem in cosmology as the problem of introducing a distance between spaces. We first introduce the spectral distance, which is a measure of closeness…
Space of spaces as a metric space
Masafumi Seriu
In spacetime physics, we frequently need to consider a set of all spaces (`universes') as a whole. In particular, the concept of `closeness' between spaces is essential. However, t…