Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Thoughts on Tachyon Cosmology   After a pedagogical review of elementary cosmology, I go on to discuss some
obstacles to obtaining inflationary or accelerating universes in M/String
Theory. In particular, I give an account of an old No-Go Theorem to this
effect. I then describe some recent ideas about the possible r\^ole of the
tachyon in cosmology. I stress that there are many objections to a naive
inflationary model based on the tachyon, but there remains the possiblity that
the tachyon was important in a possible pre-inflationary Open-String Era
preceding our present Closed String Era.

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The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
32
The categories of this paper are: atom-ph