Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantisation, Representation and Reduction; How Should We Interpret the
  Quantum Hamiltonian Constraints of Canonical Gravity?   Hamiltonian constraints feature in the canonical formulation of general
relativity. Unlike typical constraints they cannot be associated with a
reduction procedure leading to a non-trivial reduced phase space and this means
the physical interpretation of their quantum analogues is ambiguous. In
particular, can we assume that `quantisation commutes with reduction' and treat
the promotion of these constraints to operators annihilating the wave function,
according to a Dirac type procedure, as leading to a Hilbert space equivalent
to that reached by quantisation of the problematic reduced space? If not, how
should we interpret Hamiltonian constraints quantum mechanically? And on what
basis do we assert that quantisation and reduction commute anyway? These
questions will be refined and explored in the context of modern approaches to
the quantisation of canonical general relativity.

21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics