urelement
Sign in to saveAlso known as ur-element, atom, individual
In set theory, a branch of mathematics, an urelement or ur-element (from the German prefix ur-, 'primordial') is an object that is not a set, but that may be an element of a set. It is also referred to as an atom or individual. Ur-elements are also not identical with the empty set.
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Encyclopedic overview
5 sectionsContents
- Theory
- Urelements in set theory
- Quine atoms<!--'Quine atom' and 'Reflexive set' redirect here-->
- References
- External links
In set theory, a branch of mathematics, an urelement or ur-element (from the German prefix ur-, 'primordial') is an object that is not a set, but that may be an element of a set. It is also referred to as an atom or individual. Ur-elements are also not identical with the empty set.
== Theory == There are several different but essentially equivalent ways to treat urelements in a first-order theory.
Excerpted from Wikipedia’s “urelement” article, available under the CC BY-SA 4.0 licence.