Talk:Cremona group
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Name
[edit]Is this named after John Cremona? A Geek Tragedy 10:25, 2 October 2006 (UTC)
Looks like I'm not the only Wikipedian who scans arXiv/recent for interesting stuff! Melchoir 17:04, 12 October 2006 (UTC)
Cremona transformations
[edit]This article should be on Cremona transformations (which redirects here), with Cremona groups as a development of the concept. Geometry guy 00:32, 17 May 2007 (UTC)
Hard to understand
[edit]The section The Cremona group in 2 dimensions begins as follows:
"In two dimensions, Max Noether and Guido Castelnuovo showed that the complex Cremona group is generated by the standard quadratic transformation, along with , though there was some controversy about whether their proofs were correct, and Gizatullin (1983) gave a complete set of relations for these generators."
But nothing is stated about what the "standard quadratic transformation" might be, nor is any link proovided.
I hope someone knowledgeable about this subject can fill in this missing information.
Also: The introductory section contains this sentence:
"The Cremona group is naturally identified with the automorphism group of the field of the rational functions in indeterminates over, or in other words a pure transcendental extension of, with transcendence degree."
But this is a poorly written sentence. What is "in other words" ???
"Bertini involution" listed at Redirects for discussion
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The redirect Bertini involution has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at Wikipedia:Redirects for discussion/Log/2026 March 12 § Bertini involution until a consensus is reached. 1234qwer1234qwer4 03:06, 12 March 2026 (UTC)
"Geiser involution" listed at Redirects for discussion
[edit]
The redirect Geiser involution has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at Wikipedia:Redirects for discussion/Log/2026 March 12 § Geiser involution until a consensus is reached. 1234qwer1234qwer4 03:06, 12 March 2026 (UTC)