Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Foundations of the Two Measures Field Theory   Two Measures Field Theory (TMT) uses both the Riemannian volume element
\sqrt{-g}d^4x and a new one \Phi d^4x where the new measure of integration \Phi
can be build of four scalar fields. Arguments in favor of TMT, both from the
point of view of first principles and from the TMT results are summarized.
Possible origin of the TMT and symmetries that protect the structure of TMT are
reviewed. It appears that four measure scalar fields treated as "physical
coordinates" allow to define local observables in quantum gravity. The
resolution of the old cosmological constant problem as a possible direct
consequence of the TMT structure is discussed. Other applications of TMT to
cosmology and particle physics are also mentioned.

23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math