Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Causal Relations and their applications   In this work we define and study the relations between Lorentzian Manifolds
given by the diffeomorphisms which map causal future directed vectors onto
causal future directed vectors. This class of diffeomorphisms, called proper
causal relations, contains as a subset the well-known group of conformal
relations and are deeply linked to the so-called causal tensors. If two given
Lorentzian manifolds are in mutual proper causal relation then they are said to
be causally isomorphic: they are indistinguishable from the causal point of
view. Finally, the concept of causal transformations for Lorentzian manifolds
is introduced and its main mathematical properties briefly investigated.

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The categories of this paper are: funct-an
18
The categories of this paper are: econ
17
The categories of this paper are: q-fin
25
The categories of this paper are: patt-sol
19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
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The categories of this paper are: comp-gas
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The categories of this paper are: dg-ga
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The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
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The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci