Convergence in Schwartz Space of Fourier transforms?












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Let $f_n$ a sequence in Schwartz space. Suppose that $lim _{ nrightarrow infty }{ { left| { f }_{ n }-f right| }_{ alpha ,0 }=0 } $, where ${ left| f right| }_{ alpha ,0 }=underset { xin R }{ sup } { left| x right| }^{ alpha }left| fleft( x right) right|$. Is it true that its Fourier transforms converge in the same sense, in others words $lim _{ nrightarrow infty }{ { left| widehat { { f }_{ n }-f } right| }_{ alpha ,0 }= } 0$ or not?










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    No as a bound for $|widehat{f}|_{alpha,0}$ for every $alpha$ gives a bound for $|f|_{0,m}$ for every $m$
    $endgroup$
    – reuns
    Jan 8 at 4:51


















1












$begingroup$


Let $f_n$ a sequence in Schwartz space. Suppose that $lim _{ nrightarrow infty }{ { left| { f }_{ n }-f right| }_{ alpha ,0 }=0 } $, where ${ left| f right| }_{ alpha ,0 }=underset { xin R }{ sup } { left| x right| }^{ alpha }left| fleft( x right) right|$. Is it true that its Fourier transforms converge in the same sense, in others words $lim _{ nrightarrow infty }{ { left| widehat { { f }_{ n }-f } right| }_{ alpha ,0 }= } 0$ or not?










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    No as a bound for $|widehat{f}|_{alpha,0}$ for every $alpha$ gives a bound for $|f|_{0,m}$ for every $m$
    $endgroup$
    – reuns
    Jan 8 at 4:51
















1












1








1





$begingroup$


Let $f_n$ a sequence in Schwartz space. Suppose that $lim _{ nrightarrow infty }{ { left| { f }_{ n }-f right| }_{ alpha ,0 }=0 } $, where ${ left| f right| }_{ alpha ,0 }=underset { xin R }{ sup } { left| x right| }^{ alpha }left| fleft( x right) right|$. Is it true that its Fourier transforms converge in the same sense, in others words $lim _{ nrightarrow infty }{ { left| widehat { { f }_{ n }-f } right| }_{ alpha ,0 }= } 0$ or not?










share|cite|improve this question











$endgroup$




Let $f_n$ a sequence in Schwartz space. Suppose that $lim _{ nrightarrow infty }{ { left| { f }_{ n }-f right| }_{ alpha ,0 }=0 } $, where ${ left| f right| }_{ alpha ,0 }=underset { xin R }{ sup } { left| x right| }^{ alpha }left| fleft( x right) right|$. Is it true that its Fourier transforms converge in the same sense, in others words $lim _{ nrightarrow infty }{ { left| widehat { { f }_{ n }-f } right| }_{ alpha ,0 }= } 0$ or not?







convergence fourier-transform schwartz-space






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edited Jan 22 at 12:27









Davide Giraudo

128k17156268




128k17156268










asked Jan 8 at 3:01









David LlerenaDavid Llerena

254




254








  • 1




    $begingroup$
    No as a bound for $|widehat{f}|_{alpha,0}$ for every $alpha$ gives a bound for $|f|_{0,m}$ for every $m$
    $endgroup$
    – reuns
    Jan 8 at 4:51
















  • 1




    $begingroup$
    No as a bound for $|widehat{f}|_{alpha,0}$ for every $alpha$ gives a bound for $|f|_{0,m}$ for every $m$
    $endgroup$
    – reuns
    Jan 8 at 4:51










1




1




$begingroup$
No as a bound for $|widehat{f}|_{alpha,0}$ for every $alpha$ gives a bound for $|f|_{0,m}$ for every $m$
$endgroup$
– reuns
Jan 8 at 4:51






$begingroup$
No as a bound for $|widehat{f}|_{alpha,0}$ for every $alpha$ gives a bound for $|f|_{0,m}$ for every $m$
$endgroup$
– reuns
Jan 8 at 4:51












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