Talk:Minkowski's question-mark function: Difference between revisions

Revision as of 19:33, 19 January 2010

Revision as of 12:43, 18 March 2010

Line 5:

<pre>It does not have a well-defined derivative, in the classical sense, on the irrationals;</pre>That's impossible! Any monotonic function has a derivative almost everywhere. --[[User:A dergachev|a_dergachev]] ([[User talk:A dergachev|talk]]) 03:50, 8 May 2009 (UTC)

:You are absolutely correct. (See [[Monotonic function]] for example. I am not surewhat the intended statement is but I am deleting the formulation as it is now since it is clearly wrong. I am also deleting another confusing statement <pre> The derivative vanishes on the rational numbers; however, since the rationals are a set of measure zero,</pre>

<pre> this vanishing of the derivative at the rationals is not in contradiction with the non-absolute continuity of the function.

</pre>.

:There are non-absolutely continuous functions with derivatives that vanish almost everywhere (the Cantor function for example) making this statement incomprehensible.(Sorry about the confusing mark-up of my post.) --[[User:MathHisSci|MathHisSci]] ([[User talk:MathHisSci|talk]]) 12:43, 18 March 2010 (UTC)

== Comments 2005 ==