Efficiently computable, nonempty sets with no known element












1












$begingroup$


I'm looking for sets $S$ of natural numbers with the following properties:




  • There is a known efficient algorithm for determining whether a given $n$ is in $S$ (let's say "efficient" means polynomial in the number of digits of $n,$ with reasonable degree/coefficients)

  • It is known that $S$ has a small element (say below $10^{1,000}$)

  • No element of $S$ has been identified (or is likely to be found with current technology)

  • (Optional) $S$ is a singleton


One example would be the singleton $S$ containing the smaller prime factor of Reble's semiprime (a 1,084 digit number which was nonconstructively proven to be semiprime, see http://www.graysage.com/djr/isp.txt). This number has between 350 and 550 digits, and would be easy to verify if found.



What are some other examples of such sets?










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$endgroup$












  • $begingroup$
    Aren't these basically just possible outputs of an NP algorithm that isn't also P?
    $endgroup$
    – Ian
    Dec 7 '18 at 1:42










  • $begingroup$
    Well the main difficulty there is ensuring the set is nonempty. Maybe there's a well-known example that I'm unaware of.
    $endgroup$
    – Elliot Glazer
    Dec 7 '18 at 1:44
















1












$begingroup$


I'm looking for sets $S$ of natural numbers with the following properties:




  • There is a known efficient algorithm for determining whether a given $n$ is in $S$ (let's say "efficient" means polynomial in the number of digits of $n,$ with reasonable degree/coefficients)

  • It is known that $S$ has a small element (say below $10^{1,000}$)

  • No element of $S$ has been identified (or is likely to be found with current technology)

  • (Optional) $S$ is a singleton


One example would be the singleton $S$ containing the smaller prime factor of Reble's semiprime (a 1,084 digit number which was nonconstructively proven to be semiprime, see http://www.graysage.com/djr/isp.txt). This number has between 350 and 550 digits, and would be easy to verify if found.



What are some other examples of such sets?










share|cite|improve this question











$endgroup$












  • $begingroup$
    Aren't these basically just possible outputs of an NP algorithm that isn't also P?
    $endgroup$
    – Ian
    Dec 7 '18 at 1:42










  • $begingroup$
    Well the main difficulty there is ensuring the set is nonempty. Maybe there's a well-known example that I'm unaware of.
    $endgroup$
    – Elliot Glazer
    Dec 7 '18 at 1:44














1












1








1





$begingroup$


I'm looking for sets $S$ of natural numbers with the following properties:




  • There is a known efficient algorithm for determining whether a given $n$ is in $S$ (let's say "efficient" means polynomial in the number of digits of $n,$ with reasonable degree/coefficients)

  • It is known that $S$ has a small element (say below $10^{1,000}$)

  • No element of $S$ has been identified (or is likely to be found with current technology)

  • (Optional) $S$ is a singleton


One example would be the singleton $S$ containing the smaller prime factor of Reble's semiprime (a 1,084 digit number which was nonconstructively proven to be semiprime, see http://www.graysage.com/djr/isp.txt). This number has between 350 and 550 digits, and would be easy to verify if found.



What are some other examples of such sets?










share|cite|improve this question











$endgroup$




I'm looking for sets $S$ of natural numbers with the following properties:




  • There is a known efficient algorithm for determining whether a given $n$ is in $S$ (let's say "efficient" means polynomial in the number of digits of $n,$ with reasonable degree/coefficients)

  • It is known that $S$ has a small element (say below $10^{1,000}$)

  • No element of $S$ has been identified (or is likely to be found with current technology)

  • (Optional) $S$ is a singleton


One example would be the singleton $S$ containing the smaller prime factor of Reble's semiprime (a 1,084 digit number which was nonconstructively proven to be semiprime, see http://www.graysage.com/djr/isp.txt). This number has between 350 and 550 digits, and would be easy to verify if found.



What are some other examples of such sets?







computational-mathematics






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Dec 7 '18 at 1:37







Elliot Glazer

















asked Dec 7 '18 at 1:29









Elliot GlazerElliot Glazer

528139




528139












  • $begingroup$
    Aren't these basically just possible outputs of an NP algorithm that isn't also P?
    $endgroup$
    – Ian
    Dec 7 '18 at 1:42










  • $begingroup$
    Well the main difficulty there is ensuring the set is nonempty. Maybe there's a well-known example that I'm unaware of.
    $endgroup$
    – Elliot Glazer
    Dec 7 '18 at 1:44


















  • $begingroup$
    Aren't these basically just possible outputs of an NP algorithm that isn't also P?
    $endgroup$
    – Ian
    Dec 7 '18 at 1:42










  • $begingroup$
    Well the main difficulty there is ensuring the set is nonempty. Maybe there's a well-known example that I'm unaware of.
    $endgroup$
    – Elliot Glazer
    Dec 7 '18 at 1:44
















$begingroup$
Aren't these basically just possible outputs of an NP algorithm that isn't also P?
$endgroup$
– Ian
Dec 7 '18 at 1:42




$begingroup$
Aren't these basically just possible outputs of an NP algorithm that isn't also P?
$endgroup$
– Ian
Dec 7 '18 at 1:42












$begingroup$
Well the main difficulty there is ensuring the set is nonempty. Maybe there's a well-known example that I'm unaware of.
$endgroup$
– Elliot Glazer
Dec 7 '18 at 1:44




$begingroup$
Well the main difficulty there is ensuring the set is nonempty. Maybe there's a well-known example that I'm unaware of.
$endgroup$
– Elliot Glazer
Dec 7 '18 at 1:44










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