Can ratio of smooth numbers approach 1?

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Can the ratio of $q$-smooth numbers ever approach one? Asked more rigorously, can we ever have
$$1in overline{{a/b; :; a,b ;text{ are } qtext{-smooth}}}=overline{{prod_{p_ile q}p_i^{alpha_i}; :; (a_1, dots, a_{pi(q)})inmathbb{Z}^{pi(q)}}};?$$
If $q=2$, the answer is obviously no because
$$1notin overline{{2^{alpha}; :; alphainmathbb{Z}}}={0}cup {2^{alpha}; :; alphainmathbb{Z}}$$
however beyond this the problem is not easy. The reason I would like to know this is because this would imply that
$$G(q)=inf {a/b; :; a>b,; a,b ; qtext{-smooth}}>1.$$
I suspect that we may be able to say even further that
$$overline{{prod_{p_ile q}p_i^{alpha_i}; :; (a_1, dots, a_{pi(q)})inmathbb{Z}^{pi(q)}}}={0}cup {prod_{p_ile q}p_i^{alpha_i}; :; (a_1, dots, a_{pi(q)})inmathbb{Z}^{pi(q)}}$$
which would clearly imply the result.
number-theory limits elementary-number-theory
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up vote
4
down vote
favorite
Can the ratio of $q$-smooth numbers ever approach one? Asked more rigorously, can we ever have
$$1in overline{{a/b; :; a,b ;text{ are } qtext{-smooth}}}=overline{{prod_{p_ile q}p_i^{alpha_i}; :; (a_1, dots, a_{pi(q)})inmathbb{Z}^{pi(q)}}};?$$
If $q=2$, the answer is obviously no because
$$1notin overline{{2^{alpha}; :; alphainmathbb{Z}}}={0}cup {2^{alpha}; :; alphainmathbb{Z}}$$
however beyond this the problem is not easy. The reason I would like to know this is because this would imply that
$$G(q)=inf {a/b; :; a>b,; a,b ; qtext{-smooth}}>1.$$
I suspect that we may be able to say even further that
$$overline{{prod_{p_ile q}p_i^{alpha_i}; :; (a_1, dots, a_{pi(q)})inmathbb{Z}^{pi(q)}}}={0}cup {prod_{p_ile q}p_i^{alpha_i}; :; (a_1, dots, a_{pi(q)})inmathbb{Z}^{pi(q)}}$$
which would clearly imply the result.
number-theory limits elementary-number-theory
Quite amusingly, this is on the sitewide hot questions list.
– Matt Samuel
Nov 3 at 22:40
@MattSamuel: Probably because people like to hear "smooth" talk? =P
– user21820
Nov 4 at 3:02
add a comment |
up vote
4
down vote
favorite
up vote
4
down vote
favorite
Can the ratio of $q$-smooth numbers ever approach one? Asked more rigorously, can we ever have
$$1in overline{{a/b; :; a,b ;text{ are } qtext{-smooth}}}=overline{{prod_{p_ile q}p_i^{alpha_i}; :; (a_1, dots, a_{pi(q)})inmathbb{Z}^{pi(q)}}};?$$
If $q=2$, the answer is obviously no because
$$1notin overline{{2^{alpha}; :; alphainmathbb{Z}}}={0}cup {2^{alpha}; :; alphainmathbb{Z}}$$
however beyond this the problem is not easy. The reason I would like to know this is because this would imply that
$$G(q)=inf {a/b; :; a>b,; a,b ; qtext{-smooth}}>1.$$
I suspect that we may be able to say even further that
$$overline{{prod_{p_ile q}p_i^{alpha_i}; :; (a_1, dots, a_{pi(q)})inmathbb{Z}^{pi(q)}}}={0}cup {prod_{p_ile q}p_i^{alpha_i}; :; (a_1, dots, a_{pi(q)})inmathbb{Z}^{pi(q)}}$$
which would clearly imply the result.
number-theory limits elementary-number-theory
Can the ratio of $q$-smooth numbers ever approach one? Asked more rigorously, can we ever have
$$1in overline{{a/b; :; a,b ;text{ are } qtext{-smooth}}}=overline{{prod_{p_ile q}p_i^{alpha_i}; :; (a_1, dots, a_{pi(q)})inmathbb{Z}^{pi(q)}}};?$$
If $q=2$, the answer is obviously no because
$$1notin overline{{2^{alpha}; :; alphainmathbb{Z}}}={0}cup {2^{alpha}; :; alphainmathbb{Z}}$$
however beyond this the problem is not easy. The reason I would like to know this is because this would imply that
$$G(q)=inf {a/b; :; a>b,; a,b ; qtext{-smooth}}>1.$$
I suspect that we may be able to say even further that
$$overline{{prod_{p_ile q}p_i^{alpha_i}; :; (a_1, dots, a_{pi(q)})inmathbb{Z}^{pi(q)}}}={0}cup {prod_{p_ile q}p_i^{alpha_i}; :; (a_1, dots, a_{pi(q)})inmathbb{Z}^{pi(q)}}$$
which would clearly imply the result.
number-theory limits elementary-number-theory
number-theory limits elementary-number-theory
asked Nov 3 at 21:19


Will Fisher
3,487629
3,487629
Quite amusingly, this is on the sitewide hot questions list.
– Matt Samuel
Nov 3 at 22:40
@MattSamuel: Probably because people like to hear "smooth" talk? =P
– user21820
Nov 4 at 3:02
add a comment |
Quite amusingly, this is on the sitewide hot questions list.
– Matt Samuel
Nov 3 at 22:40
@MattSamuel: Probably because people like to hear "smooth" talk? =P
– user21820
Nov 4 at 3:02
Quite amusingly, this is on the sitewide hot questions list.
– Matt Samuel
Nov 3 at 22:40
Quite amusingly, this is on the sitewide hot questions list.
– Matt Samuel
Nov 3 at 22:40
@MattSamuel: Probably because people like to hear "smooth" talk? =P
– user21820
Nov 4 at 3:02
@MattSamuel: Probably because people like to hear "smooth" talk? =P
– user21820
Nov 4 at 3:02
add a comment |
2 Answers
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6
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accepted
Yes, if $qge 3$.
This is because $log_2(3)$ is irrational, so the fractional parts of $log_2(3^n)$ lie densely in $[0,1)$. In particular they can become arbitrarily small.
add a comment |
up vote
6
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Yes. We can just consider fractions of the form $frac {3^a}{2^b}$. The base $2$ log of this is $alog_2(3)-b$. Because $log_2(3)$ is irrational, we can choose $a,b$ to make this difference arbitrarily close to $0$, which means the ratio can be arbitrarily close to $1$.
add a comment |
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
6
down vote
accepted
Yes, if $qge 3$.
This is because $log_2(3)$ is irrational, so the fractional parts of $log_2(3^n)$ lie densely in $[0,1)$. In particular they can become arbitrarily small.
add a comment |
up vote
6
down vote
accepted
Yes, if $qge 3$.
This is because $log_2(3)$ is irrational, so the fractional parts of $log_2(3^n)$ lie densely in $[0,1)$. In particular they can become arbitrarily small.
add a comment |
up vote
6
down vote
accepted
up vote
6
down vote
accepted
Yes, if $qge 3$.
This is because $log_2(3)$ is irrational, so the fractional parts of $log_2(3^n)$ lie densely in $[0,1)$. In particular they can become arbitrarily small.
Yes, if $qge 3$.
This is because $log_2(3)$ is irrational, so the fractional parts of $log_2(3^n)$ lie densely in $[0,1)$. In particular they can become arbitrarily small.
edited Nov 3 at 21:44
answered Nov 3 at 21:26
Henning Makholm
234k16299532
234k16299532
add a comment |
add a comment |
up vote
6
down vote
Yes. We can just consider fractions of the form $frac {3^a}{2^b}$. The base $2$ log of this is $alog_2(3)-b$. Because $log_2(3)$ is irrational, we can choose $a,b$ to make this difference arbitrarily close to $0$, which means the ratio can be arbitrarily close to $1$.
add a comment |
up vote
6
down vote
Yes. We can just consider fractions of the form $frac {3^a}{2^b}$. The base $2$ log of this is $alog_2(3)-b$. Because $log_2(3)$ is irrational, we can choose $a,b$ to make this difference arbitrarily close to $0$, which means the ratio can be arbitrarily close to $1$.
add a comment |
up vote
6
down vote
up vote
6
down vote
Yes. We can just consider fractions of the form $frac {3^a}{2^b}$. The base $2$ log of this is $alog_2(3)-b$. Because $log_2(3)$ is irrational, we can choose $a,b$ to make this difference arbitrarily close to $0$, which means the ratio can be arbitrarily close to $1$.
Yes. We can just consider fractions of the form $frac {3^a}{2^b}$. The base $2$ log of this is $alog_2(3)-b$. Because $log_2(3)$ is irrational, we can choose $a,b$ to make this difference arbitrarily close to $0$, which means the ratio can be arbitrarily close to $1$.
answered Nov 3 at 21:27


Ross Millikan
285k23195363
285k23195363
add a comment |
add a comment |
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R,DGz6,1u0oxGh6pH9,svx
Quite amusingly, this is on the sitewide hot questions list.
– Matt Samuel
Nov 3 at 22:40
@MattSamuel: Probably because people like to hear "smooth" talk? =P
– user21820
Nov 4 at 3:02