Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Path integrals for actions that are not quadratic in their time
  derivatives   The standard way to construct a path integral is to use a Legendre
transformation to find the hamiltonian, to repeatedly insert complete sets of
states into the time-evolution operator, and then to integrate over the
momenta. This procedure is simple when the action is quadratic in its time
derivatives, but in most other cases Legendre's transformation is intractable,
and the hamiltonian is unknown. This paper shows how to construct path
integrals when one can't find the hamiltonian because the first time
derivatives of the fields occur in ways that make a Legendre transformation
intractable; it focuses on scalar fields and does not discuss higher-derivative
theories or those in which some fields lack time derivatives.

17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int