Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Producing 3d Ricci flows with non-negative Ricci curvature via singular
  Ricci flows   We extend the concept of singular Ricci flow by Kleiner and Lott from 3d
compact manifolds to 3d complete manifolds with possibly unbounded curvature.
As an application of the generalized singular Ricci flow, we show that for any
3d complete Riemannian manifold with non-negative Ricci curvature, there exists
a smooth Ricci flow starting from it.

14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
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The categories of this paper are: acc-phys
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs
19
The categories of this paper are: eess
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The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio