The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.
a political unit formed by joining monarchical states under the crown of one sovereign.
In state law, two types of union are distinguished—personal and organic. A personal union may arise whenever, as a result of dynastic ties and the order of succession, one person becomes the monarch of two or more states; in this way, for example, England and Hanover were joined in a union from 1714 to 1837. States joined in a personal union retain their own sovereignty, and the power of the monarch is nominal.
An organic union may be formed on the basis of a treaty, as in the case of the union of Sweden and Norway from 1814 to 1905, or it may be imposed by a stronger state on a weaker one, as in the case of the union of Austria and Hungary from 1867 to 1918 or the union of Denmark and Iceland from 1918 to 1944. In international relations, an organic union acts as a single sovereign state.
The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
A data structure that can store items of different types, but can store only one item at a time.
A screwed or flanged pipe coupling usually in the form of a ring fitting around the outside of the joint.
A union of a given family of sets is a set consisting of those elements that are members of at least one set in the family. Also known as join.
For two fuzzy sets A and B, the fuzzy set whose membership function has a value at any element x that is the maximum of the values of the membership functions of A and B at x.
The union of two Boolean matrices A and B, with the same number of rows and columns, is the Boolean matrix whose element cij in row i and column j is the union of corresponding elements aij in A and bij in B.
The union of two graphs is the graph whose set of vertices is the union of the sets of vertices of the two graphs, and whose set of edges is the union of the sets of edges of the two graphs.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
1. an association, alliance, or confederation of individuals or groups for a common purpose, esp political
2. a device on a flag representing union, such as another flag depicted in the top left corner
3. a device for coupling or linking parts, such as pipes
a. an association of students at a university or college formed to look after the students' interests, provide facilities for recreation, etc.
b. the building or buildings housing the facilities of such an organization
5. Maths a set containing all members of two given sets. Symbol: ∪, as in A∪B
6. in 19th-century England
a. a number of parishes united for the administration of poor relief
b. a workhouse supported by such a combination
7. Textiles a piece of cloth or fabric consisting of two different kinds of yarn
a. the union of England and Wales from 1543
b. the union of the English and Scottish crowns (1603--1707)
c. the union of England and Scotland from 1707
d. the political union of Great Britain and Ireland (1801--1920)
e. the union of Great Britain and Northern Ireland from 1920
a. the United States of America
b. the northern states of the US during the Civil War
c. (as modifier): Union supporters
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
union (set theory)
An operation on two sets
which returns the
set of all elements that are a member of either or both of the
argument sets; normally written as an infix upper-case U
symbol. The operator generalises to zero or more sets by
taking the union of the current partial result (initially the
empty set) with the next argument set, in any order.
For example, (a, b, c) U (c, d, e) = (a, b, c, d, e)
whose values may be of one of a
number of other types, thet current type depending on
conditions that are only known at run-time. A variable
union type must be allocated sufficient storage space to hold
the largest component type. Some unions include extra
information to say which type of value the union currently has
(a "tagged union"), others rely on the program to keep track
of this independently.
A union contrasts with a structure
values of all component types at once.
An SQL operator
that concatenates two result
sets, that must have the same number and types of columns.
The operator may be followed by the word "ALL" to indicate
that results that appear in both sets should appear twice in
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