Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measuring Omega   We were asked to debate the value of the cosmological mass-density parameter
Omega. Is Omega_m=1 in accordance with the simplest model? Is Omega_m much
smaller as indicated by some observations? There is conflicting evidence. We
lay out the various methods for measuring Omega_m, mention new developments and
current estimates, and focus on prospects versus the associated difficulties.
We try to shed light on the uncertainties that are responsible for the span of
estimates for Omega_m.
  We divide the methods into the following four classes:
  a. Global measures of the properties of space-time that constrain
combinations of Omega_m and the other cosmological parameters (Lambda, Ho, to).
  b. Virialized Systems. Nonlinear dynamics within galaxies and clusters on
comoving scales 1-10 Mpc/h.
  c. Large-scale structure. Mildly-nonlinear gravitational dynamics of
fluctuations on scales 10-100 Mpc/h, in particular cosmic flows.
  d. Growth rate of fluctuations from the last scattering of the CMB or from
high redshift galaxies to the present.
  Methods (b) typically yield low values of Omega_m=0.2-0.3. Methods (a) and
(c) typically indicate higher values of Omega_m=0.4-1.

32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph