Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Do SNe Ia Provide Direct Evidence for Past Deceleration of the Universe?   Observations of SN 1997ff at z ~ 1.7 favor the accelerating Universe
interpretation of the high-redshift type Ia supernova data over simple models
of intergalactic dust or SN luminosity evolution. Taken at face-value, they
provide direct lines of evidence that the Universe was decelerating in the
past, an expected but untested feature of the current cosmological model. We
show that the strength of this conclusion depends upon the nature of the dark
energy causing the present acceleration. Only for a cosmological constant is
the SNe evidence definitive. Using a new test which is independent of the
contents of the Universe, we show that the SN data favor recent acceleration (z
< 0.5) and past deceleration (z > 0.5).

26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
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The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs