Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Geometry of null hypersurfaces   We review some basic natural geometric objects on null hypersurfaces.
Gauss-Codazzi constraints are given in terms of the analog of canonical ADM
momentum which is a well defined tensor density on the null surface. Bondi
cones are analyzed with the help of this object.

22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
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The categories of this paper are: eess
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
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The categories of this paper are: econ
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The categories of this paper are: nlin
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The categories of this paper are: bayes-an
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol