Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: No Open or Flat Bouncing Cosmologies in Einstein Gravity   We show that bouncing open or flat Friedmann-Robertson-Walker cosmologies are
inconsistent with worldsheet string theory to first approximation.
Specifically, the Virasoro constraint translates to the null energy condition
in spacetime at leading order in the alpha-prime expansion. Thus one must go
beyond minimally-coupled Einstein gravity in order to find bounce solutions.

16
The categories of this paper are: stat
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga
25
The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg