Talk:Surjective function

message: if a surjective function is revrsible, how does the first picture there represent a reversible function. The C appears to be mapped to by two elements of the domain; wouldn't that make it no surjective? anton — Preceding unsigned comment added by 142.157.122.230 (talk) 15:39, 16 August 2007 (UTC)
replies: text: It's not very clear in the article.  "Reversible" simply means that if g(C) = 4, f(4) = C.  It doesn't matter that g(C) can also equal 3.  I'm going to try to put that into the article.  --KSnortum (talk) 20:52, 25 November 2007 (UTC)
thread_title:  Reversible and Inverse 

message: I think the images here are exceptionally good. I might add an example of an actual function that is surjective, but not bijective such as  f(x)=x \cdot sin(x) 
Just noticed that this is a cool example of the product of two odd functions being an even function :)
Lfahlberg (talk) 06:27, 29 June 2013 (UTC)
replies: text: Since nobody objected I added an example (without an image) of a surjective, but not bijective function.Lfahlberg (talk) 15:36, 6 August 2013 (UTC)
thread_title:  Example of a actual function that is surjective but not bijective with image 

message: I like this page, but would someone please add a table of the different arrow symbols that are commonly used for onto, one-one, etc?  It would also be nice to note the LaTeX commands for the symbols. Jfgrcar (talk) 20:02, 2 June 2014 (UTC)
replies: text: I just inserted a template which links to a page describing some of the notation.  This does not explain all of the symbols but it should help. — Anita5192 (talk) 01:18, 3 June 2014 (UTC)
thread_title:  Arrow Symbols 

message: According to the wiki-definition of a function, the title of this page is wrong. 
 A function f from X to Y is a subset of the Cartesian product X × Y subject to the following condition: 
 every element of X is the first component of one and only one ordered pair in the subset.
This, however, is obviously not surjective. The most used term in numerous books would be surjective map or mapping, but not function. Should we change the title? 
— ManniFaltig (talk) 20:47, 22 June 2014 (UTC)
replies: text: Your point is not clear. Not all functions are surjective (unless you are a member of that small minority who don't believe in the concept of a codomain – Y in the above definition.) Bill Cherowitzo  (talk) 04:55, 23 June 2014 (UTC)
thread_title:  Function? 

message: In my understanding surjectivity allows the existence of members of the domain that are not mapped into any element of the codomain. This is not visible in any of the pictures on this page and neither on https://en.wikipedia.org/wiki/Bijection,_injection_and_surjection csavlovs  , Sep 16 2016  — Preceding unsigned comment added by 109.103.73.15 (talk) 06:32, 16 September 2016 (UTC)
replies: text: Nope. If there were elements of the domain that were not mapped to anything in the codomain, then this would not be a function (it would be a proper partial function) and this article is about surjective functions. --Bill Cherowitzo  (talk) 16:12, 16 September 2016 (UTC)
thread_title:  Clarification needed for the pictures  

message: * Greek: Επιρριπτική συνάρτηση
(SURJECTIVE = επιρριπτική, INJECTIVE = ερριπτική, BIJECTIVE = αμφιρριπτική)  — Preceding unsigned comment added by 2A02:587:4115:1000:B854:2FD1:F18D:DC09 (talk) 22:10, 18 July 2019 (UTC)
thread_title:  Translations 

message: Please write "iff" and not "if",  
and referencing a couple of web-sites instead
of a math text book is not a good idea
Jan Burse (talk) 10:30, 30 July 2022 (UTC)
thread_title:  Sloppy Definition