Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Mechanics, cosmology and Mach's principle   It is pointed out that recent cosmological findings seem to support the view
that the mass/energy distribution of the universe defines the Newtonian
inertial frames as originally suggested by Mach. The background concepts of
inertial frame, Newton's second law, and fictitious forces are clarified. A
precise definition of Mach's principle is suggested. Then an approximation to
general relativity discovered by Einstein, Infeld, and Hoffmann is used and it
is found that this precise formulation of Mach's principle is realized provided
the mass/energy density of the universe has a specific value. This value turns
out to be twice the critical density. The implications of this approximate
result is put into context.

13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con