Timeline for What are usual notations for surjective, injective and bijective functions?
Current License: CC BY-SA 3.0
10 events
| when toggle format | what | by | license | comment | |
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| Oct 6, 2018 at 9:05 | comment | added | Mr Pie | I quite like another idea: mathoverflow.net/questions/42929/suggestions-for-good-notation/… | |
| Nov 29, 2016 at 9:54 | comment | added | stranger | @JSchlather Try \mathbin{\rightarrowtail \hspace{-8pt} \twoheadrightarrow} which gives: $\mathbin{\rightarrowtail \hspace{-8pt} \twoheadrightarrow}$ | |
| Jun 21, 2011 at 21:22 | comment | added | JSchlather | There's an easy fix to combine the two into one, similar to Theo's but a bit shorter use just \hspace except negative so we can get stuff like $\rightarrowtail \hspace{-8pt} \rightarrow$ and $\hookrightarrow \hspace{-8pt} \rightarrow$, just by doing '\rightarrowtail \hspace{-8pt} \rightarrow' and '\hookrightarrow \hspace{-8pt} \rightarrow'. Although there is an issue with the rightarrowtail being a bit small. | |
| Jun 21, 2011 at 17:58 | comment | added | t.b. |
@John: I agree, it was just a demonstration for Asaf. I have never seen such an arrow in an official LaTeX font, but you can produce these things in diagrams using the xypic-package.
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| Jun 21, 2011 at 17:56 | comment | added | John Bentin | @Theo: The the two non-tail arrowheads on the bijection arrow should be close together, exactly as on the surjection, with the arrow body the same length as the others; that is, the bijection is exactly the superimposition of injection and surjection (which is why I like it!). | |
| Jun 21, 2011 at 12:54 | comment | added | t.b. |
@Asaf: I think John wants something like this $\displaystyle\rightarrowtail\!\!\!\!\!\rightarrow$ (I used \rightarrowtail\!\!\!\!\!\rightarrow - which is of course an ugly hack)
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| Jun 21, 2011 at 12:48 | comment | added | Asaf Karagila♦ |
@Willie, John: $\rightarrowtail$ I assume and it is \rightarrowtail (from the commonly used amssymb)
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| Jun 21, 2011 at 12:42 | comment | added | Willie Wong | Sounds like a good question for our sister site | |
| Jun 21, 2011 at 12:27 | vote | accept | jimjim | ||
| Jun 21, 2011 at 12:01 | history | answered | John Bentin | CC BY-SA 3.0 |