Find $f$ such that : $f$ is absolutely integrable, $f'$ is absolutely integrable and such that $f$ is not...











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I am trying to find a function $f: mathbb{R}^+ to mathbb{R}^+$ that fullfils the following conditions





  • $$f in mathcal{C}^1(mathbb{R}^+,mathbb{R}^+)$$


  • $$int_{mathbb{R}^+} f in mathbb{R}^+$$


  • $$int_{mathbb{R}^+} mid f' mid in mathbb{R}$$


  • $$f text{is not $frac{1}{2}$-Hölder}$$





I've tried functions with smooth spikes but I am unable to express this function as combinations of usual functions.



Moreover, I know from this post that if $f'^2$ is integrable then $f$ is necessarily $frac{1}{2}-$Hölder.



Thank you.



Note: all the integrals are taken in the Riemann sense.










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  • what does your second integral mean?
    – zhw.
    2 days ago












  • @zhw I am sorry, this was a typo. It should be better now.
    – IBPsilly
    2 days ago















up vote
6
down vote

favorite
1












I am trying to find a function $f: mathbb{R}^+ to mathbb{R}^+$ that fullfils the following conditions





  • $$f in mathcal{C}^1(mathbb{R}^+,mathbb{R}^+)$$


  • $$int_{mathbb{R}^+} f in mathbb{R}^+$$


  • $$int_{mathbb{R}^+} mid f' mid in mathbb{R}$$


  • $$f text{is not $frac{1}{2}$-Hölder}$$





I've tried functions with smooth spikes but I am unable to express this function as combinations of usual functions.



Moreover, I know from this post that if $f'^2$ is integrable then $f$ is necessarily $frac{1}{2}-$Hölder.



Thank you.



Note: all the integrals are taken in the Riemann sense.










share|cite|improve this question









New contributor




IBPsilly is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.




















  • what does your second integral mean?
    – zhw.
    2 days ago












  • @zhw I am sorry, this was a typo. It should be better now.
    – IBPsilly
    2 days ago













up vote
6
down vote

favorite
1









up vote
6
down vote

favorite
1






1





I am trying to find a function $f: mathbb{R}^+ to mathbb{R}^+$ that fullfils the following conditions





  • $$f in mathcal{C}^1(mathbb{R}^+,mathbb{R}^+)$$


  • $$int_{mathbb{R}^+} f in mathbb{R}^+$$


  • $$int_{mathbb{R}^+} mid f' mid in mathbb{R}$$


  • $$f text{is not $frac{1}{2}$-Hölder}$$





I've tried functions with smooth spikes but I am unable to express this function as combinations of usual functions.



Moreover, I know from this post that if $f'^2$ is integrable then $f$ is necessarily $frac{1}{2}-$Hölder.



Thank you.



Note: all the integrals are taken in the Riemann sense.










share|cite|improve this question









New contributor




IBPsilly is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











I am trying to find a function $f: mathbb{R}^+ to mathbb{R}^+$ that fullfils the following conditions





  • $$f in mathcal{C}^1(mathbb{R}^+,mathbb{R}^+)$$


  • $$int_{mathbb{R}^+} f in mathbb{R}^+$$


  • $$int_{mathbb{R}^+} mid f' mid in mathbb{R}$$


  • $$f text{is not $frac{1}{2}$-Hölder}$$





I've tried functions with smooth spikes but I am unable to express this function as combinations of usual functions.



Moreover, I know from this post that if $f'^2$ is integrable then $f$ is necessarily $frac{1}{2}-$Hölder.



Thank you.



Note: all the integrals are taken in the Riemann sense.







calculus real-analysis integration indefinite-integrals sobolev-spaces






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edited 15 hours ago









RGS

8,85111129




8,85111129






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asked 2 days ago









IBPsilly

514




514




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IBPsilly is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






IBPsilly is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.












  • what does your second integral mean?
    – zhw.
    2 days ago












  • @zhw I am sorry, this was a typo. It should be better now.
    – IBPsilly
    2 days ago


















  • what does your second integral mean?
    – zhw.
    2 days ago












  • @zhw I am sorry, this was a typo. It should be better now.
    – IBPsilly
    2 days ago
















what does your second integral mean?
– zhw.
2 days ago






what does your second integral mean?
– zhw.
2 days ago














@zhw I am sorry, this was a typo. It should be better now.
– IBPsilly
2 days ago




@zhw I am sorry, this was a typo. It should be better now.
– IBPsilly
2 days ago















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