universe of discourse

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universe of discourse

In ontology, the set of all entities that can be represented in some declarative language or other formal system.

Each entity is represented by a name and may have some human-readable description of its meaning. Formal axioms constrain the interpretation and well-formed use of these names.
This article is provided by FOLDOC - Free Online Dictionary of Computing (foldoc.org)
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Universe of Discourse


a class (set) of objects considered within a given context. A context here is understood to mean a distinct discourse or a sentence expressing a distinct discourse, a collection of sentences, a fragment of a scientific theory, or an entire theory. In number theory, the universe of discourse in the natural-number series (the set of nonnegative integers); in mathematical analysis, the set of real numbers; in botany, the set of all plants (more precisely, the set of all plant species); and in the predicate calculus or logic of classes, any fixed nonempty domain. The universe of discourse is also referred to as the universal set, the opposite in logic and set theory of what is known as the empty set; the empty set contains no object of a given type and is the complement of the universal set.

The generally accepted idea of a universe of discourse as a given domain of objects was proposed by J. Venn. In number theory, according to this definition, the complement of the set of even numbers is the set of odd numbers and not the “set of all conceivable objects, none of which is an even number”— which would include, for example, this encyclopedia and everything in the world other than the even numbers. This definition has replaced G. Frege’s concept of a “universal” universe of discourse, which had led to paradoxes.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
In linear adaptation, the base MFs defined over a universe of discourse of B = [l, u] are adapted to the context-adapted universe of discourse by means of a linear transformation function shown in (6), where U = [a,b] is used to represent the bounds of the adapted MF:
Suppose that [mu] is the fuzzy measure in the universe of discourse X = {[x.sub.1], [x.sub.2], ..., [x.sub.n]} and v([DELTA][[??].sub.i]) is a set of intuitionistic trapezoidal fuzzy prospect value function of [[??].sub.i] = ([[a.sub.i], [b.sub.i], [c.sub.i], [d.sub.i]] [[mu].sub.i], [v.sub.i], (i = 1, 2, ..., n).
5) Let [S.sub.1] and [S.sub.2] be two extension sets, in the universe of discourse U, such that they have no common end points, and [S.sub.1] [subset] [S.sub.2].
In this case Dan's imperfect assimilation of the Northern universe of discourse has interfered with his communication with Muriel.
It is observed in the experiment that prediction can improved by taking appropriate number of sub intervals of the universe of discourse. Table 4 shows the average forecasting error for different fuzzy sets.
An expression is specific if the speaker uses it to refer to a particular entity in the universe of discourse, which may be identifiable or nonidentifiable; otherwise it is nonspecific.
Here the square represents the universe of discourse. This consists of V plus not-V.(2) Clearly V is equivalent to A in Dumont's diagram and not-V to his B.
Now, each of these three philosophers theorizes cross-culturally within a single universe of discourse. This universe comprises commonplace objects (for Danto) or physical objects (for Margolis) or performed objects such as violins (for Wolterstorff).
It would appear from the universe of discourse, especially in first volume, that both advocates and critics of Marx are implicitly accepting Samuelson's gibe that Marx was a minor post-Ricardian.
Definition: [35] Let U be a universe of discourse and A the neutrosophic set A [subset] U.
[18,19] used the intuitionistic fuzzy c-means clustering algorithm to get unequal intervals of the universe of discourse, and they also used the trace-back mechanism and vector quantization to forecast.