Talk:Necessary and sufficient

From Citizendium
Jump to navigation Jump to search
This article is developed but not approved.
Main Article
Discussion
Related Articles  [?]
Bibliography  [?]
External Links  [?]
Citable Version  [?]
 
To learn how to update the categories for this article, see here. To update categories, edit the metadata template.
 Definition In mathematics, a frequently used phrase to say that two statements are logically equivalent. [d] [e]
Checklist and Archives
 Workgroup category Mathematics [Please add or review categories]
 Talk Archive none  English language variant British English

Circle

"A circle (in the plane) is usually defined as a curve such that its points all have the same distance from a given point" — a bit problematic; say, half a circle, is it also a circle? It IS "a curve such that its points all have the same distance from a given point", isn't it? Boris Tsirelson 10:05, 2 February 2010 (UTC)

True, of course. I wanted to keep this colloquial, and there this distinction is usually not made. (It holds for both characterizations.) And since I did not think of the formulation I found now ...
By the way: Boris, do you think (agree) that this topic is worth a page (for non-mathematicians) like this?
--Peter Schmitt 10:36, 2 February 2010 (UTC)
It was a bit unexpected for me. However, why not? It could help. And you are not the first to try such things (but probably one of the first ten). Look at site of Timothy Gowers, especially, "Miscellaneous" (near the end). Boris Tsirelson 16:12, 2 February 2010 (UTC)