Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Higher-Dimensional Communication and S.E.T.I   In cosmologies with more than four dimensions, of the type required for
unification, it is possible for signals to have velocities in excess of that of
light. Using a five-dimensional model which otherwise agrees with observations,
two subjects are reviewed: (a) An exact solution of the field equations which
describes a 4D spacetime with a large cosmological constant and waves
travelling in ordinary 3D space with velocities exceeding lightspeed. (b) An
example where the 4D interval or proper time is modulated by the systematic
variation of the scalar field associated with the fifth dimension, providing a
simple signalling method. These and related consequences of higher-dimensional
cosmology have significant implications for astrophysics, and especially the
Search for Extraterrestrial Intelligence.

29
The categories of this paper are: funct-an
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci