Union (set theory) (English Wikipedia)

Smith, Douglas; Eggen, Maurice; Andre, Richard St (2014-08-01). A Transition to Advanced Mathematics. Cengage Learning. ISBN 9781285463261.
Pierpont, James (1912). Lectures On The Theory Of Functions Of Real Variables Vol II. Osmania University, Digital Library Of India. Ginn And Company.

books.google.com (Global: 3^rd place; English: 3^rd place)

Vereshchagin, Nikolai Konstantinovich; Shen, Alexander (2002-01-01). Basic Set Theory. American Mathematical Soc. ISBN 9780821827314.
deHaan, Lex; Koppelaars, Toon (2007-10-25). Applied Mathematics for Database Professionals. Apress. ISBN 9781430203483.
Dasgupta, Abhijit (2013-12-11). Set Theory: With an Introduction to Real Point Sets. Springer Science & Business Media. ISBN 9781461488545.
Halmos, P. R. (2013-11-27). Naive Set Theory. Springer Science & Business Media. ISBN 9781475716450.

doi.org (Global: 2^nd place; English: 2^nd place)

Cantor, Georg (1895-11-01). "Beiträge zur Begründung der transfiniten Mengenlehre". Mathematische Annalen (in German). 46 (4): 481–512. doi:10.1007/BF02124929. ISSN 1432-1807.
Oxford English Dictionary, “union (n.2), sense III.17,” March 2025, https://doi.org/10.1093/OED/1665274057

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"Etymology of "union" by etymonline". etymonline. Retrieved 2025-04-10.

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"MathCS.org - Real Analysis: Theorem 1.1.4: De Morgan's Laws". mathcs.org. Retrieved 2024-10-22.

probabilitycourse.com (Global: low place; English: low place)

"Set Operations | Union | Intersection | Complement | Difference | Mutually Exclusive | Partitions | De Morgan's Law | Distributive Law | Cartesian Product". Probability Course. Retrieved 2020-09-05.

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"Finite Union of Finite Sets is Finite". ProofWiki. Archived from the original on 11 September 2014. Retrieved 29 April 2018.

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Cantor, Georg (1895-11-01). "Beiträge zur Begründung der transfiniten Mengenlehre". Mathematische Annalen (in German). 46 (4): 481–512. doi:10.1007/BF02124929. ISSN 1432-1807.

st-andrews.ac.uk (Global: 1,547^th place; English: 1,410^th place)

mathshistory.st-andrews.ac.uk

"Earliest Uses of Symbols of Set Theory and Logic". Maths History. Retrieved 2025-04-10.

uml.edu (Global: low place; English: low place)

faculty.uml.edu

Doerr, Al; Levasseur, Ken. ADS Laws of Set Theory.

umsl.edu (Global: 8,618^th place; English: 7,478^th place)

"The algebra of sets - Wikipedia, the free encyclopedia". www.umsl.edu. Retrieved 2024-10-22.

unicode.org (Global: 311^th place; English: 239^th place)

"The Unicode Standard, Version 15.0 – Mathematical Operators – Range: 2200–22FF" (PDF). Unicode. p. 3.

web.archive.org (Global: 1^st place; English: 1^st place)

Weisstein, Eric W. "Union". Wolfram Mathworld. Archived from the original on 2009-02-07. Retrieved 2009-07-14.
"Finite Union of Finite Sets is Finite". ProofWiki. Archived from the original on 11 September 2014. Retrieved 29 April 2018.

wolfram.com (Global: 513^th place; English: 537^th place)

mathworld.wolfram.com

Weisstein, Eric W. "Union". Wolfram Mathworld. Archived from the original on 2009-02-07. Retrieved 2009-07-14.

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Cantor, Georg (1895-11-01). "Beiträge zur Begründung der transfiniten Mengenlehre". Mathematische Annalen (in German). 46 (4): 481–512. doi:10.1007/BF02124929. ISSN 1432-1807.

Union (set theory) (English Wikipedia)

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mathshistory.st-andrews.ac.uk

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st-andrews.ac.uk (Global: 1,547^th place; English: 1,410^th place)

umsl.edu (Global: 8,618^th place; English: 7,478^th place)

unicode.org (Global: 311^th place; English: 239^th place)

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