Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Measuring the metric: a parametrized post-Friedmanian approach to the
  cosmic dark energy problem   We argue for a ``parametrized post-Friedmanian'' approach to linear
cosmology, where the history of expansion and perturbation growth is measured
without assuming that the Einstein Field Equations hold. As an illustration, a
model-independent analysis of 92 type Ia supernovae demonstrates that the curve
giving the expansion history has the wrong shape to be explained without some
form of dark energy or modified gravity. We discuss how upcoming lensing,
galaxy clustering, cosmic microwave background and Lyman alpha forest
observations can be combined to pursue this program, which generalizes the
quest for a dark energy equation of state, and forecast the accuracy that the
proposed SNAP satellite can attain.

23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
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
10
The categories of this paper are: q-bio