Timeline for A diagonal operation on power series
Current License: CC BY-SA 3.0
16 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 16, 2015 at 16:11 | answer | added | L. Dumont | timeline score: 7 | |
| S Aug 20, 2012 at 10:14 | vote | accept | HCH | ||
| Aug 20, 2012 at 10:14 | vote | accept | HCH | ||
| S Aug 20, 2012 at 10:14 | |||||
| Aug 20, 2012 at 0:16 | vote | accept | HCH | ||
| Aug 20, 2012 at 10:14 | |||||
| Aug 19, 2012 at 23:53 | vote | accept | HCH | ||
| Aug 20, 2012 at 0:16 | |||||
| S Aug 19, 2012 at 23:53 | vote | accept | HCH | ||
| Aug 19, 2012 at 23:53 | |||||
| Aug 19, 2012 at 23:53 | vote | accept | HCH | ||
| S Aug 19, 2012 at 23:53 | |||||
| Aug 16, 2012 at 23:13 | comment | added | Gerry Myerson | Also worth a look: van der Poorten and Lipshitz, Rational functions, diagonals, automata and arithmetic, in Number Theory (Banff, AB, 1988), 339–358, de Gruyter, Berlin, 1990, MR1106672 (93b:11095). | |
| Aug 16, 2012 at 16:55 | answer | added | Qiaochu Yuan | timeline score: 7 | |
| Aug 16, 2012 at 16:38 | comment | added | Pietro Majer | Nice! Actually I wasn't thinking to a particular context, that in any case has to be fixed (even though I'd had bet rational functions were ok!) | |
| Aug 16, 2012 at 16:10 | answer | added | Igor Rivin | timeline score: 5 | |
| Aug 16, 2012 at 15:27 | comment | added | fedja | @Pietro What you wrote is a really good mind-boggling exercise for the students: if your formula were correct, $\Delta f$ would be rational for rational $f$ (computing the residue of a rational function requires a few differentiations only and they cannot kill the rational dependence on the parameter $t$). It took me 3 full minutes to discover the error, so I do not want to deprive the others from the pleasure of figuring it out by themselves :). | |
| Aug 16, 2012 at 15:03 | comment | added | Pietro Majer | What about $\Delta(f)(t)=\mathrm{Res}_{z=0} f(tz,1/z)/z$ | |
| Aug 16, 2012 at 15:02 | comment | added | Igor Rivin | That is, you give an example (which works for me) but what book do you know which discusses these matters? | |
| Aug 16, 2012 at 15:01 | comment | added | Igor Rivin | When you say "it is known that", do you have a reference? | |
| Aug 16, 2012 at 13:45 | history | asked | HCH | CC BY-SA 3.0 |