# Abstract Set

(Redirected from Unordered Set)

## References

### 2013

• (Wikipedia, 2013) ⇒ http://en.wikipedia.org/wiki/Set_(mathematics) Retrieved:2013-12-1.
• In mathematics, a set is a collection of distinct objects, considered as an object in its own right. For example, the numbers 2, 4, and 6 are distinct objects when considered separately, but when they are considered collectively they form a single set of size three, written {2,4,6}. Sets are one of the most fundamental concepts in mathematics. Developed at the end of the 19th century, set theory is now a ubiquitous part of mathematics, and can be used as a foundation from which nearly all of mathematics can be derived. In mathematics education, elementary topics such as Venn Diagrams are taught at a young age, while more advanced concepts are taught as part of a university degree. The term itself was coined by Bolzano in his work The Paradoxes of the Infinite.

### 2009

• http://en.wiktionary.org/wiki/set
• A matching collection of similar things; A collection of various objects for a particular purpose; An object made up of several parts; A well-defined collection of mathematical objects and elements, often having a common property; (informal) Set theory; A group of people, usually meeting ...

• (Wikipedia, 2009) ⇒ http://en.wikipedia.org/wiki/Set_(category_theory)
• In mathematics, the category of sets, denoted as Set, is the category whose objects are all sets and whose morphisms are all functions. ...
• http://planetmath.org/encyclopedia/Set.html
• Sets can be of “real” objects or mathematical objects, but the sets themselves are purely conceptual. This is an important point to note: the set of all cows (for example) does not physically exist, even though the cows do. The set is a “gathering” of the cows into one conceptual unit that is not part of physical reality. This makes it easy to see why we can have sets with an infinite number of elements; even though we may not be able to point out infinitely many objects in the real world, we can construct conceptual sets with an infinite number of elements.