and mention some possible applications of such
discourse-analyzing systems.
By default, each part of the sentence has its own
referents which do not depend on any referents
belonging to other parts of the sentence (the function
α will search for dependencies). Most of these
referents (belonging to certain interpreters in the
richly structured worldlet system defined in Section
1: r
1
, r
2
,...) refer to entities existing in the external
world, while other referents can be eventual (e
i
),
temporal (t
j
) or spatial (s
k
).
An eventual referent must be assigned to all
verbs, nouns, adjectives and adverbs (parts of speech
which can, in principle, play a predicative role in the
sentence). For example, the noun banker and the
adjective clever both can be treated as eventualities
“being a banker” and “being clever”. Function σ,
taking the label Π into account (which, as mentioned
in Section 1, contains information on the already-
analyzed syntactic structures), assigns the
argumental (r
i
), temporal and spatial referents to the
eventual referent of the regent and forms the
structure pred(e, t, s, r
1
, r
2
, …) (one should note that
only a small part of the referents play a significant
role in the actual discourse).
The anchoring function α assigns the referents to
each other in different worldlets, thereby declaring
some referents as identical, which induces an
equivalence relation. This process, however, should
be aided by an ontology (apart from the information
collected during the syntactic analysis) as mentioned
in section 2. The ontology can have an arbitrary
structure – for example, if we take the basics of
psycholinguistics into account, the semantic web of
the mental lexicon could be modeled by a neuron
network (and, in general, RL could be used to handle
lexical semantics). The mental lexicon has multiple
dimensions on its own, and these dimensions can be
regarded as multiple relation types in the network –
or, even more precisely, a network of networks. If
we have no ontology at all, only the referents of
literally identical syntactic entities (and, in some
cases, pronouns) can be anchored to each other.
The ontology is also used when we try to
determine whether the discourse being analyzed is
coherent or not. In (3d), the computerized equivalent
of the semantic web should be used to determine
coherence (by using a metric to measure the distance
between the concepts (semantic categories)
WEDDING and PRIEST). If the (semantic) distance
is sufficiently low, the discourse can be regarded as
coherent. Of course, if we use RL technology to
create our ontology, the semantic proximity between
two (or more) concepts must be pre-taught.
Summarizing the above, the actual identity of
referents can be determined by using the relation
types (such as synonimity, semantic priming etc.)
and distance metrics in the network.
The set of temporal referents (t
i
) can be regarded
as a partially ordered set (see, say, (3e)). As we
mentioned above, referents can be identified by
using a distance metric on the semantic web, thereby
fuzzifying the process of determining discourse
coherence. Many temporal adverbs are fuzzy by
their nature (e.g. nowadays, a long time ago, shortly)
and they are not even culturally independent. But
even if we only handle well-defined temporal
referents, the system still has some important
applications (see Section 4 below).
The level function λ (practically) assigns the
referents to certain worldlets of interpreters (such as
those of their beliefs, desires, intentions, dreams).
The entities of the external (real) world (model)
always exist and they are “seen” and referenced by
all interpreters. But during the syntactic analysis,
level-changing words (mostly adverbs or particles)
are found, expressing modality. “If only Mary had a
car! Me, too, could drive it occasionally.”
The phrase “if only” refers to the speaker’s
desire, rendering all referents in its scope to a
different level, also a different worldlet (expressing a
desire of the speaker). Entities on this level do not
exist in the real world but the speaker must refer to
them in order to express his/her desire.
Certain values of the cursor κ can be regarded as
quasi-constant since they do not depend on the
actual discourse flow directly and, in most cases,
they do not need to be set during the analysis.
“Then” is set at the beginning of a story and, for
example, “You” can point to the user, who (as an
agent) must always be considered as an active
participant in the discourses being analyzed. Many
applications of the system are based on this. We will
show some of them in the next section.
4 APPLICATONS AND PLANS
As we mentioned above, the aim of our ℜeALIS
model is automatic discourse analysis. To do this,
we need to implement all the above-described tasks
and functions. But why should an interpreter based
on ℜeALIS be implemented?
First, expert systems can be created by
implementing the ℜeALIS model. This depends on
the ontology on which the function α is based. The
ontologies need not to include everything or be over-
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