Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Non-existence of Irreversible Processes in Compact Space Time   It is shown that if physical space time were truly compact there would only
be of the order of one solutions to the classical field equations with a
weighting to be explained. But that would not allow any peculiar choice of
initial conditions that could support a non-trivial second law of
thermodynamics. We present a no-go theorem: Irreversible processes would be
extremely unlikely to occur, for the almost unique solution for the
intrinsically compact space time world, although irreversible processes are
well known to occur in general.What we here assume -- compact space time --
excludes that universe could exist eternally.

11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
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The categories of this paper are: stat
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The categories of this paper are: math-ph