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Emil Jeřábek
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GivenLet $k,n\in\mathbb{N}$$k,m\in\mathbb{N}$ be given. Let M:={0,... , m-1}$M:=\{0,... , m-1\}$. How to find a subset $T\subset M$, |T|=k with T={ $n_1$,...,$n_k$ | $n_i\in M$ } and T+T|={ (a+b)%m |$|T|=k$ such that $a\in N,b\in N$$|T+T|$ is maximal, where }$T+T=\{ (a+b)\mathbin\%m \mid a\in T,b\in T \}$ ("%"“%” means modulo) such that |T+T| is max.?

I tried to construct a sequence of numbers which maximize |T+T|$|T+T|$. But I couln'tcouldn’t figure out:
 

  • isIs it possible to cover the whole set M$M$ for $k\leq \sqrt{n}$
    $k\leq \sqrt{m}$?
  • What is the best way to construct such a sequence in Theory.theory?

I am looking for papers which deals with this topic or any word to find those papers. I don'tdon’t think this problem is running under the ordinary topicname "settopic name “set covering problems"problems”.

My Ideaidea to construct such a sequence is $a_0=0;a_{i+1}=a_i+(k-i)$ for T={$a_i$, i=0,...,k-1}$T=\{a_i\mid i=0,...,k-1\}$ to get as lesssmall number of collisions as possible collision inamong the sums of |T+T|in $T+T$. But random subsets of M$M$ show me, that there are better subsets.

In my opinion it is hard to find such aan optimal subset T$T$.

Sorry for my bad englishEnglish.

Given $k,n\in\mathbb{N}$. Let M:={0,... , m-1}. How to find a subset $T\subset M$, |T|=k with T={ $n_1$,...,$n_k$ | $n_i\in M$ } and T+T|={ (a+b)%m | $a\in N,b\in N$ } ("%" means modulo) such that |T+T| is max.

I tried to construct a sequence of numbers which maximize |T+T|. But I couln't figure out:
 

  • is it possible to cover the whole set M for $k\leq \sqrt{n}$
  • What is the best way to construct such a sequence in Theory.

I am looking for papers which deals with this topic or any word to find those papers. I don't think this problem is running under the ordinary topicname "set covering problems".

My Idea to construct such a sequence is $a_0=0;a_{i+1}=a_i+(k-i)$ for T={$a_i$, i=0,...,k-1} to get as less as possible collision in the sums of |T+T|. But random subsets of M show me, that there are better subsets.

In my opinion it is hard to find such a optimal subset T.

Sorry for my bad english.

Let $k,m\in\mathbb{N}$ be given. Let $M:=\{0,... , m-1\}$. How to find a subset $T\subset M$, $|T|=k$ such that $|T+T|$ is maximal, where $T+T=\{ (a+b)\mathbin\%m \mid a\in T,b\in T \}$ (“%” means modulo)?

I tried to construct a sequence of numbers which maximize $|T+T|$. But I couldn’t figure out:

  • Is it possible to cover the whole set $M$ for $k\leq \sqrt{m}$?
  • What is the best way to construct such a sequence in theory?

I am looking for papers which deals with this topic or any word to find those papers. I don’t think this problem is running under the ordinary topic name “set covering problems”.

My idea to construct such a sequence is $a_0=0;a_{i+1}=a_i+(k-i)$ for $T=\{a_i\mid i=0,...,k-1\}$ to get as small number of collisions as possible among the sums in $T+T$. But random subsets of $M$ show me that there are better subsets.

In my opinion it is hard to find such an optimal subset $T$.

Sorry for my bad English.

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Optimize / simple Set Covering Problem

Given $k,n\in\mathbb{N}$. Let M:={0,... , m-1}. How to find a subset $T\subset M$, |T|=k with T={ $n_1$,...,$n_k$ | $n_i\in M$ } and T+T|={ (a+b)%m | $a\in N,b\in N$ } ("%" means modulo) such that |T+T| is max.

I tried to construct a sequence of numbers which maximize |T+T|. But I couln't figure out:

  • is it possible to cover the whole set M for $k\leq \sqrt{n}$
  • What is the best way to construct such a sequence in Theory.

I am looking for papers which deals with this topic or any word to find those papers. I don't think this problem is running under the ordinary topicname "set covering problems".

My Idea to construct such a sequence is $a_0=0;a_{i+1}=a_i+(k-i)$ for T={$a_i$, i=0,...,k-1} to get as less as possible collision in the sums of |T+T|. But random subsets of M show me, that there are better subsets.

In my opinion it is hard to find such a optimal subset T.

Sorry for my bad english.