Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Deductive Database System LDL++   This paper describes the LDL++ system and the research advances that have
enabled its design and development. We begin by discussing the new nonmonotonic
and nondeterministic constructs that extend the functionality of the LDL++
language, while preserving its model-theoretic and fixpoint semantics. Then, we
describe the execution model and the open architecture designed to support
these new constructs and to facilitate the integration with existing DBMSs and
applications. Finally, we describe the lessons learned by using LDL++ on
various tested applications, such as middleware and datamining.

37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
27
The categories of this paper are: comp-gas