Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effective Theories and Modifications of Gravity   We live at a time of contradictory messages about how successfully we
understand gravity. General Relativity seems to work very well in the Earth's
immediate neighborhood, but arguments abound that it needs modification at very
small and/or very large distances. This essay tries to put this discussion into
the broader context of similar situations in other areas of physics, and
summarizes some of the lessons which our good understanding of gravity in the
solar system has for proponents for its modification over very long and very
short distances. The main message is that effective theories, in the technical
sense of `effective', provide the natural language for testing proposals, and
so are also effective in the colloquial sense.

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The categories of this paper are: cs
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
35
The categories of this paper are: mtrl-th
23
The categories of this paper are: solv-int