Distribution of prime numbers modulo $4$
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Are primes equally likely to be equivalent to $1$ or $3$ modulo $4,$ or is there a skew in one direction?
That is my specific question, but I would be interested to know if there exists a trend more generally, say for modulo any even.
number-theory prime-numbers
$endgroup$
add a comment |
$begingroup$
Are primes equally likely to be equivalent to $1$ or $3$ modulo $4,$ or is there a skew in one direction?
That is my specific question, but I would be interested to know if there exists a trend more generally, say for modulo any even.
number-theory prime-numbers
$endgroup$
add a comment |
$begingroup$
Are primes equally likely to be equivalent to $1$ or $3$ modulo $4,$ or is there a skew in one direction?
That is my specific question, but I would be interested to know if there exists a trend more generally, say for modulo any even.
number-theory prime-numbers
$endgroup$
Are primes equally likely to be equivalent to $1$ or $3$ modulo $4,$ or is there a skew in one direction?
That is my specific question, but I would be interested to know if there exists a trend more generally, say for modulo any even.
number-theory prime-numbers
number-theory prime-numbers
edited 3 mins ago
YuiTo Cheng
2,65641037
2,65641037
asked 30 mins ago
Will SeathWill Seath
414
414
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
Despite of Chebychev's bias (more primes with residue $3$ occur usually in practice), in the long run, the ratio is $1:1$.
$endgroup$
1
$begingroup$
I would also note for future reference that the proof is given as an immediate consequence of Dirichlet’s Theorem and in general the primes are equidistributed modulo every $d$ with approximately $frac{1}{phi(d)}$ in each class.
$endgroup$
– Μάρκος Καραμέρης
23 mins ago
1
$begingroup$
Generalization of Chebyshev's biase : The primes with a quadratic non-residue usually occur more often in practice than the primes with a quadratic residue.
$endgroup$
– Peter
21 mins ago
$begingroup$
Interesting I haven't heard of that generalization before, is there any reason other than empirical evidence that this happens?
$endgroup$
– Μάρκος Καραμέρης
17 mins ago
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I only know that Chebyshev noticed this phenomenon, no idea whether it has a mathematical reason. Also interesting : In the "race" between primes of the form $4k+1$ and $4k+3$ it is known that the lead switches infinite many often.
$endgroup$
– Peter
14 mins ago
add a comment |
$begingroup$
In general, if $gcd(a,b) = 1$, the number of primes which are of the form $b$ modulo $a$ is asymptotic to $dfrac{pi(x)}{varphi(a)}$ where $pi(x)$ is the number of primes $le x$. As you see the asymptotic formula is independent of $b$ hence for a given modulo all residues occur equally in the long run.
$endgroup$
1
$begingroup$
(for $b$ coprime to $a$, of course)
$endgroup$
– Robert Israel
18 mins ago
$begingroup$
Yes of course ... updated :)
$endgroup$
– Nilotpal Kanti Sinha
17 mins ago
add a comment |
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2 Answers
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active
oldest
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2 Answers
2
active
oldest
votes
active
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votes
active
oldest
votes
$begingroup$
Despite of Chebychev's bias (more primes with residue $3$ occur usually in practice), in the long run, the ratio is $1:1$.
$endgroup$
1
$begingroup$
I would also note for future reference that the proof is given as an immediate consequence of Dirichlet’s Theorem and in general the primes are equidistributed modulo every $d$ with approximately $frac{1}{phi(d)}$ in each class.
$endgroup$
– Μάρκος Καραμέρης
23 mins ago
1
$begingroup$
Generalization of Chebyshev's biase : The primes with a quadratic non-residue usually occur more often in practice than the primes with a quadratic residue.
$endgroup$
– Peter
21 mins ago
$begingroup$
Interesting I haven't heard of that generalization before, is there any reason other than empirical evidence that this happens?
$endgroup$
– Μάρκος Καραμέρης
17 mins ago
$begingroup$
I only know that Chebyshev noticed this phenomenon, no idea whether it has a mathematical reason. Also interesting : In the "race" between primes of the form $4k+1$ and $4k+3$ it is known that the lead switches infinite many often.
$endgroup$
– Peter
14 mins ago
add a comment |
$begingroup$
Despite of Chebychev's bias (more primes with residue $3$ occur usually in practice), in the long run, the ratio is $1:1$.
$endgroup$
1
$begingroup$
I would also note for future reference that the proof is given as an immediate consequence of Dirichlet’s Theorem and in general the primes are equidistributed modulo every $d$ with approximately $frac{1}{phi(d)}$ in each class.
$endgroup$
– Μάρκος Καραμέρης
23 mins ago
1
$begingroup$
Generalization of Chebyshev's biase : The primes with a quadratic non-residue usually occur more often in practice than the primes with a quadratic residue.
$endgroup$
– Peter
21 mins ago
$begingroup$
Interesting I haven't heard of that generalization before, is there any reason other than empirical evidence that this happens?
$endgroup$
– Μάρκος Καραμέρης
17 mins ago
$begingroup$
I only know that Chebyshev noticed this phenomenon, no idea whether it has a mathematical reason. Also interesting : In the "race" between primes of the form $4k+1$ and $4k+3$ it is known that the lead switches infinite many often.
$endgroup$
– Peter
14 mins ago
add a comment |
$begingroup$
Despite of Chebychev's bias (more primes with residue $3$ occur usually in practice), in the long run, the ratio is $1:1$.
$endgroup$
Despite of Chebychev's bias (more primes with residue $3$ occur usually in practice), in the long run, the ratio is $1:1$.
edited 13 mins ago
answered 27 mins ago
PeterPeter
49.3k1240138
49.3k1240138
1
$begingroup$
I would also note for future reference that the proof is given as an immediate consequence of Dirichlet’s Theorem and in general the primes are equidistributed modulo every $d$ with approximately $frac{1}{phi(d)}$ in each class.
$endgroup$
– Μάρκος Καραμέρης
23 mins ago
1
$begingroup$
Generalization of Chebyshev's biase : The primes with a quadratic non-residue usually occur more often in practice than the primes with a quadratic residue.
$endgroup$
– Peter
21 mins ago
$begingroup$
Interesting I haven't heard of that generalization before, is there any reason other than empirical evidence that this happens?
$endgroup$
– Μάρκος Καραμέρης
17 mins ago
$begingroup$
I only know that Chebyshev noticed this phenomenon, no idea whether it has a mathematical reason. Also interesting : In the "race" between primes of the form $4k+1$ and $4k+3$ it is known that the lead switches infinite many often.
$endgroup$
– Peter
14 mins ago
add a comment |
1
$begingroup$
I would also note for future reference that the proof is given as an immediate consequence of Dirichlet’s Theorem and in general the primes are equidistributed modulo every $d$ with approximately $frac{1}{phi(d)}$ in each class.
$endgroup$
– Μάρκος Καραμέρης
23 mins ago
1
$begingroup$
Generalization of Chebyshev's biase : The primes with a quadratic non-residue usually occur more often in practice than the primes with a quadratic residue.
$endgroup$
– Peter
21 mins ago
$begingroup$
Interesting I haven't heard of that generalization before, is there any reason other than empirical evidence that this happens?
$endgroup$
– Μάρκος Καραμέρης
17 mins ago
$begingroup$
I only know that Chebyshev noticed this phenomenon, no idea whether it has a mathematical reason. Also interesting : In the "race" between primes of the form $4k+1$ and $4k+3$ it is known that the lead switches infinite many often.
$endgroup$
– Peter
14 mins ago
1
1
$begingroup$
I would also note for future reference that the proof is given as an immediate consequence of Dirichlet’s Theorem and in general the primes are equidistributed modulo every $d$ with approximately $frac{1}{phi(d)}$ in each class.
$endgroup$
– Μάρκος Καραμέρης
23 mins ago
$begingroup$
I would also note for future reference that the proof is given as an immediate consequence of Dirichlet’s Theorem and in general the primes are equidistributed modulo every $d$ with approximately $frac{1}{phi(d)}$ in each class.
$endgroup$
– Μάρκος Καραμέρης
23 mins ago
1
1
$begingroup$
Generalization of Chebyshev's biase : The primes with a quadratic non-residue usually occur more often in practice than the primes with a quadratic residue.
$endgroup$
– Peter
21 mins ago
$begingroup$
Generalization of Chebyshev's biase : The primes with a quadratic non-residue usually occur more often in practice than the primes with a quadratic residue.
$endgroup$
– Peter
21 mins ago
$begingroup$
Interesting I haven't heard of that generalization before, is there any reason other than empirical evidence that this happens?
$endgroup$
– Μάρκος Καραμέρης
17 mins ago
$begingroup$
Interesting I haven't heard of that generalization before, is there any reason other than empirical evidence that this happens?
$endgroup$
– Μάρκος Καραμέρης
17 mins ago
$begingroup$
I only know that Chebyshev noticed this phenomenon, no idea whether it has a mathematical reason. Also interesting : In the "race" between primes of the form $4k+1$ and $4k+3$ it is known that the lead switches infinite many often.
$endgroup$
– Peter
14 mins ago
$begingroup$
I only know that Chebyshev noticed this phenomenon, no idea whether it has a mathematical reason. Also interesting : In the "race" between primes of the form $4k+1$ and $4k+3$ it is known that the lead switches infinite many often.
$endgroup$
– Peter
14 mins ago
add a comment |
$begingroup$
In general, if $gcd(a,b) = 1$, the number of primes which are of the form $b$ modulo $a$ is asymptotic to $dfrac{pi(x)}{varphi(a)}$ where $pi(x)$ is the number of primes $le x$. As you see the asymptotic formula is independent of $b$ hence for a given modulo all residues occur equally in the long run.
$endgroup$
1
$begingroup$
(for $b$ coprime to $a$, of course)
$endgroup$
– Robert Israel
18 mins ago
$begingroup$
Yes of course ... updated :)
$endgroup$
– Nilotpal Kanti Sinha
17 mins ago
add a comment |
$begingroup$
In general, if $gcd(a,b) = 1$, the number of primes which are of the form $b$ modulo $a$ is asymptotic to $dfrac{pi(x)}{varphi(a)}$ where $pi(x)$ is the number of primes $le x$. As you see the asymptotic formula is independent of $b$ hence for a given modulo all residues occur equally in the long run.
$endgroup$
1
$begingroup$
(for $b$ coprime to $a$, of course)
$endgroup$
– Robert Israel
18 mins ago
$begingroup$
Yes of course ... updated :)
$endgroup$
– Nilotpal Kanti Sinha
17 mins ago
add a comment |
$begingroup$
In general, if $gcd(a,b) = 1$, the number of primes which are of the form $b$ modulo $a$ is asymptotic to $dfrac{pi(x)}{varphi(a)}$ where $pi(x)$ is the number of primes $le x$. As you see the asymptotic formula is independent of $b$ hence for a given modulo all residues occur equally in the long run.
$endgroup$
In general, if $gcd(a,b) = 1$, the number of primes which are of the form $b$ modulo $a$ is asymptotic to $dfrac{pi(x)}{varphi(a)}$ where $pi(x)$ is the number of primes $le x$. As you see the asymptotic formula is independent of $b$ hence for a given modulo all residues occur equally in the long run.
edited 10 mins ago
Peter
49.3k1240138
49.3k1240138
answered 20 mins ago
Nilotpal Kanti SinhaNilotpal Kanti Sinha
4,73821641
4,73821641
1
$begingroup$
(for $b$ coprime to $a$, of course)
$endgroup$
– Robert Israel
18 mins ago
$begingroup$
Yes of course ... updated :)
$endgroup$
– Nilotpal Kanti Sinha
17 mins ago
add a comment |
1
$begingroup$
(for $b$ coprime to $a$, of course)
$endgroup$
– Robert Israel
18 mins ago
$begingroup$
Yes of course ... updated :)
$endgroup$
– Nilotpal Kanti Sinha
17 mins ago
1
1
$begingroup$
(for $b$ coprime to $a$, of course)
$endgroup$
– Robert Israel
18 mins ago
$begingroup$
(for $b$ coprime to $a$, of course)
$endgroup$
– Robert Israel
18 mins ago
$begingroup$
Yes of course ... updated :)
$endgroup$
– Nilotpal Kanti Sinha
17 mins ago
$begingroup$
Yes of course ... updated :)
$endgroup$
– Nilotpal Kanti Sinha
17 mins ago
add a comment |
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