Alternating harmonic series containing floor function

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Let $$Sleft(aright)=sum_n=0^infty fracleft(-1right)^left[naright]left[naright]+1$$

where $agt 0$, and $left[cdotright]$ denotes the floor function.

Consider $ain mathbbQ$, we can conclude that not all $a$ can make $Sleft(aright)$ converge.

In particular, we have $Sleft(frac1kright)=kln 2$.

Let $$A=leftamid Sleft(aright):convergesright$$

My questions are:

•Does $A$ contain any irrational numbers?

•Is $A$ an uncountable set? A full-measure set?

•If so, I would guess the following limit $$lim_ain A, arightarrow 0^+a, Sleft(aright)$$ exists and gets $ln 2$. Am I right?







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    Let $$Sleft(aright)=sum_n=0^infty fracleft(-1right)^left[naright]left[naright]+1$$

    where $agt 0$, and $left[cdotright]$ denotes the floor function.

    Consider $ain mathbbQ$, we can conclude that not all $a$ can make $Sleft(aright)$ converge.

    In particular, we have $Sleft(frac1kright)=kln 2$.

    Let $$A=leftamid Sleft(aright):convergesright$$

    My questions are:

    •Does $A$ contain any irrational numbers?

    •Is $A$ an uncountable set? A full-measure set?

    •If so, I would guess the following limit $$lim_ain A, arightarrow 0^+a, Sleft(aright)$$ exists and gets $ln 2$. Am I right?







    share|cite|improve this question
























      up vote
      3
      down vote

      favorite
      1









      up vote
      3
      down vote

      favorite
      1






      1





      Let $$Sleft(aright)=sum_n=0^infty fracleft(-1right)^left[naright]left[naright]+1$$

      where $agt 0$, and $left[cdotright]$ denotes the floor function.

      Consider $ain mathbbQ$, we can conclude that not all $a$ can make $Sleft(aright)$ converge.

      In particular, we have $Sleft(frac1kright)=kln 2$.

      Let $$A=leftamid Sleft(aright):convergesright$$

      My questions are:

      •Does $A$ contain any irrational numbers?

      •Is $A$ an uncountable set? A full-measure set?

      •If so, I would guess the following limit $$lim_ain A, arightarrow 0^+a, Sleft(aright)$$ exists and gets $ln 2$. Am I right?







      share|cite|improve this question














      Let $$Sleft(aright)=sum_n=0^infty fracleft(-1right)^left[naright]left[naright]+1$$

      where $agt 0$, and $left[cdotright]$ denotes the floor function.

      Consider $ain mathbbQ$, we can conclude that not all $a$ can make $Sleft(aright)$ converge.

      In particular, we have $Sleft(frac1kright)=kln 2$.

      Let $$A=leftamid Sleft(aright):convergesright$$

      My questions are:

      •Does $A$ contain any irrational numbers?

      •Is $A$ an uncountable set? A full-measure set?

      •If so, I would guess the following limit $$lim_ain A, arightarrow 0^+a, Sleft(aright)$$ exists and gets $ln 2$. Am I right?









      share|cite|improve this question













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      share|cite|improve this question








      edited Aug 10 at 14:06

























      asked Aug 9 at 16:58









      Antimonius

      3017




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