Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reinstating Schwarzschild's original manifold and its singularity   The content of this review is summarized here through the titles of its
sections, as follows:
  1. Introduction: Schwarzschild's original solution and the ``Schwarzschild
solution''.
  2. The wrong arrow of time of Hilbert's manifold is at the origin of the
Kruskal extension.
  3. An invariant, local, intrinsic quantity that diverges at the Schwarzschild
surface.
  4. The singularity at the Schwarzschild surface is both intrinsic and
physical.
  5. Conclusion.

25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
6
The categories of this paper are: astro-ph
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
24
The categories of this paper are: dg-ga