129 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
7 papers
Spatially inhomogeneous and irrotational geometries admitting Intrinsic Conformal Symmetries
Pantelis S. Apostolopoulos
"Diagonal" spatially inhomogeneous (SI) models are introduced under the assumption of the existence of (proper) intrinsic symmetries and can be seen, in some sense, complementary t…
Intrinsic Conformal Symmetries in Szekeres models
Pantelis S. Apostolopoulos
We show that Spatially Inhomogeneous (SI) and Irrotational dust models admit a \emph{6-dimensional algebra } of \emph{Intrinsic Conformal Vector Fields} (ICVFs) sa…
Szekeres models: a covariant approach
Pantelis S. Apostolopoulos
We exploit the 1+1+2 formalism to covariantly describe the inhomogeneous and anisotropic Szekeres models. It is shown that an \emph{average scale length} can be defined \emph{covar…
Vacuum self similar anisotropic cosmologies in gravity
Pantelis S. Apostolopoulos
The implications from the existence of a proper Homothetic Vector Field (HVF) on the dynamics of vacuum anisotropic models in gravitational theory are studied. The fact that…
Efficiency of ETV diagrams as diagnostic tools for long-term period variations. II. Non-conservative mass transfer, and gravitational radiation
N. Nanouris, A. Kalimeris, E. Antonopoulou +1
The credibility of an eclipse timing variation (ETV) diagram analysis is investigated for various manifestations of the mass transfer and gravitational radiation processes in binar…
On the folded normal distribution
Michail Tsagris, Christina Beneki, Hossein Hassani
The characteristic function of the folded normal distribution and its moment function are derived. The entropy of the folded normal distribution and the Kullback--Leibler from the…
On the recent seismic activity at Kefalonia island (Greece): Manifestations of an Earth system in critical state
Y. Contoyiannis, S. M. Potirakis, J. Kopanas +4
In this paper we show, in terms of fracture-induced electromagnetic emissions (EME) that the Earth system around the focal areas came to critical condition a few days before the oc…