Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The supernova rate: a critical ingredient and an important tool   In this review I summarize the role of supernova rate as a critical
ingredient of modern astrophysics, and as an important tool to understand SN
explosions. Many years of active observations and theoretical modeling have
produced several important results. In particular, linking SN rates with parent
stellar populations has proved to be an important strategy. Despite these
advances, the situation is far from clear, in particular for the SNe Ia.

2
The categories of this paper are: math
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg