If gcd(a,b) = 1, can any integer be written as a linear combination of a,b?
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I am thinking about this in the context of the two water jugs problem. I know that a jug of capacity n can be filled if gcd(a,b) | n. Does this have the corollary that any integer can be written as a linear combination of a and b if gcd(a,b) = 1.
combinatorics number-theory elementary-number-theory puzzle
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I am thinking about this in the context of the two water jugs problem. I know that a jug of capacity n can be filled if gcd(a,b) | n. Does this have the corollary that any integer can be written as a linear combination of a and b if gcd(a,b) = 1.
combinatorics number-theory elementary-number-theory puzzle
New contributor
Yes, that is right
â DonAntonio
34 mins ago
If $gcd(a,b) = 1$ then there are $c,d $ such that $ac+bd = 1$ and hence if $p$ is an integer we can write $p = (cp)a + (dp)b$.
â copper.hat
32 mins ago
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up vote
1
down vote
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up vote
1
down vote
favorite
I am thinking about this in the context of the two water jugs problem. I know that a jug of capacity n can be filled if gcd(a,b) | n. Does this have the corollary that any integer can be written as a linear combination of a and b if gcd(a,b) = 1.
combinatorics number-theory elementary-number-theory puzzle
New contributor
I am thinking about this in the context of the two water jugs problem. I know that a jug of capacity n can be filled if gcd(a,b) | n. Does this have the corollary that any integer can be written as a linear combination of a and b if gcd(a,b) = 1.
combinatorics number-theory elementary-number-theory puzzle
combinatorics number-theory elementary-number-theory puzzle
New contributor
New contributor
New contributor
asked 35 mins ago
taurus
82
82
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New contributor
Yes, that is right
â DonAntonio
34 mins ago
If $gcd(a,b) = 1$ then there are $c,d $ such that $ac+bd = 1$ and hence if $p$ is an integer we can write $p = (cp)a + (dp)b$.
â copper.hat
32 mins ago
add a comment |Â
Yes, that is right
â DonAntonio
34 mins ago
If $gcd(a,b) = 1$ then there are $c,d $ such that $ac+bd = 1$ and hence if $p$ is an integer we can write $p = (cp)a + (dp)b$.
â copper.hat
32 mins ago
Yes, that is right
â DonAntonio
34 mins ago
Yes, that is right
â DonAntonio
34 mins ago
If $gcd(a,b) = 1$ then there are $c,d $ such that $ac+bd = 1$ and hence if $p$ is an integer we can write $p = (cp)a + (dp)b$.
â copper.hat
32 mins ago
If $gcd(a,b) = 1$ then there are $c,d $ such that $ac+bd = 1$ and hence if $p$ is an integer we can write $p = (cp)a + (dp)b$.
â copper.hat
32 mins ago
add a comment |Â
2 Answers
2
active
oldest
votes
up vote
4
down vote
accepted
Yes that's a consequence of Bézout's identity which can be proved by Euclidean algorithm and which states that
$$forall a,bin mathbbZquad gcd(a,b)=1 iff exists x,yin mathbbZquad ax+by=1$$
from which we obtain that
$$acdot nx+bcdot ny=n$$
@copper.hat Thanks for the editing, the fact is that I've also encountered that as "Bezout's theorem" but "Bezout's identity" seems to be the official name.
â gimusi
28 mins ago
Bézout's theorem is usually interpreted in the context of algebraic geometry,
â copper.hat
27 mins ago
@copper.hat Indeed I'm completely unaware about algebraic geometry :)
â gimusi
25 mins ago
Thank you very much!
â taurus
23 mins ago
add a comment |Â
up vote
0
down vote
In general, if $d=gcd(a,b)$, then any integer of the form $nd$ for some integer $n$ can be expressed as a linear combination of $a$ and $b$. This is because we can write $a=da_1$ and $b=db_1$ for integers $a_1,b_1$ so that $gcd(a_1,b_1)=1$. By the euclidean algorithm this leads us to the fact that there exists $k_1,k_2$ such that
$$1=k_1a_1+k_2b_1$$
for all $a_1,b_1$. Multiplying both sides of the equation by $nd$, we get
$$nd=nk_1(da_1)+nk_2(db_1)=nk_1a+nk_2b$$
Which gives us a way to find anything of the form $nd$ as a linear combination of $a,b$.
add a comment |Â
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
4
down vote
accepted
Yes that's a consequence of Bézout's identity which can be proved by Euclidean algorithm and which states that
$$forall a,bin mathbbZquad gcd(a,b)=1 iff exists x,yin mathbbZquad ax+by=1$$
from which we obtain that
$$acdot nx+bcdot ny=n$$
@copper.hat Thanks for the editing, the fact is that I've also encountered that as "Bezout's theorem" but "Bezout's identity" seems to be the official name.
â gimusi
28 mins ago
Bézout's theorem is usually interpreted in the context of algebraic geometry,
â copper.hat
27 mins ago
@copper.hat Indeed I'm completely unaware about algebraic geometry :)
â gimusi
25 mins ago
Thank you very much!
â taurus
23 mins ago
add a comment |Â
up vote
4
down vote
accepted
Yes that's a consequence of Bézout's identity which can be proved by Euclidean algorithm and which states that
$$forall a,bin mathbbZquad gcd(a,b)=1 iff exists x,yin mathbbZquad ax+by=1$$
from which we obtain that
$$acdot nx+bcdot ny=n$$
@copper.hat Thanks for the editing, the fact is that I've also encountered that as "Bezout's theorem" but "Bezout's identity" seems to be the official name.
â gimusi
28 mins ago
Bézout's theorem is usually interpreted in the context of algebraic geometry,
â copper.hat
27 mins ago
@copper.hat Indeed I'm completely unaware about algebraic geometry :)
â gimusi
25 mins ago
Thank you very much!
â taurus
23 mins ago
add a comment |Â
up vote
4
down vote
accepted
up vote
4
down vote
accepted
Yes that's a consequence of Bézout's identity which can be proved by Euclidean algorithm and which states that
$$forall a,bin mathbbZquad gcd(a,b)=1 iff exists x,yin mathbbZquad ax+by=1$$
from which we obtain that
$$acdot nx+bcdot ny=n$$
Yes that's a consequence of Bézout's identity which can be proved by Euclidean algorithm and which states that
$$forall a,bin mathbbZquad gcd(a,b)=1 iff exists x,yin mathbbZquad ax+by=1$$
from which we obtain that
$$acdot nx+bcdot ny=n$$
edited 30 mins ago
answered 32 mins ago
gimusi
78.1k73889
78.1k73889
@copper.hat Thanks for the editing, the fact is that I've also encountered that as "Bezout's theorem" but "Bezout's identity" seems to be the official name.
â gimusi
28 mins ago
Bézout's theorem is usually interpreted in the context of algebraic geometry,
â copper.hat
27 mins ago
@copper.hat Indeed I'm completely unaware about algebraic geometry :)
â gimusi
25 mins ago
Thank you very much!
â taurus
23 mins ago
add a comment |Â
@copper.hat Thanks for the editing, the fact is that I've also encountered that as "Bezout's theorem" but "Bezout's identity" seems to be the official name.
â gimusi
28 mins ago
Bézout's theorem is usually interpreted in the context of algebraic geometry,
â copper.hat
27 mins ago
@copper.hat Indeed I'm completely unaware about algebraic geometry :)
â gimusi
25 mins ago
Thank you very much!
â taurus
23 mins ago
@copper.hat Thanks for the editing, the fact is that I've also encountered that as "Bezout's theorem" but "Bezout's identity" seems to be the official name.
â gimusi
28 mins ago
@copper.hat Thanks for the editing, the fact is that I've also encountered that as "Bezout's theorem" but "Bezout's identity" seems to be the official name.
â gimusi
28 mins ago
Bézout's theorem is usually interpreted in the context of algebraic geometry,
â copper.hat
27 mins ago
Bézout's theorem is usually interpreted in the context of algebraic geometry,
â copper.hat
27 mins ago
@copper.hat Indeed I'm completely unaware about algebraic geometry :)
â gimusi
25 mins ago
@copper.hat Indeed I'm completely unaware about algebraic geometry :)
â gimusi
25 mins ago
Thank you very much!
â taurus
23 mins ago
Thank you very much!
â taurus
23 mins ago
add a comment |Â
up vote
0
down vote
In general, if $d=gcd(a,b)$, then any integer of the form $nd$ for some integer $n$ can be expressed as a linear combination of $a$ and $b$. This is because we can write $a=da_1$ and $b=db_1$ for integers $a_1,b_1$ so that $gcd(a_1,b_1)=1$. By the euclidean algorithm this leads us to the fact that there exists $k_1,k_2$ such that
$$1=k_1a_1+k_2b_1$$
for all $a_1,b_1$. Multiplying both sides of the equation by $nd$, we get
$$nd=nk_1(da_1)+nk_2(db_1)=nk_1a+nk_2b$$
Which gives us a way to find anything of the form $nd$ as a linear combination of $a,b$.
add a comment |Â
up vote
0
down vote
In general, if $d=gcd(a,b)$, then any integer of the form $nd$ for some integer $n$ can be expressed as a linear combination of $a$ and $b$. This is because we can write $a=da_1$ and $b=db_1$ for integers $a_1,b_1$ so that $gcd(a_1,b_1)=1$. By the euclidean algorithm this leads us to the fact that there exists $k_1,k_2$ such that
$$1=k_1a_1+k_2b_1$$
for all $a_1,b_1$. Multiplying both sides of the equation by $nd$, we get
$$nd=nk_1(da_1)+nk_2(db_1)=nk_1a+nk_2b$$
Which gives us a way to find anything of the form $nd$ as a linear combination of $a,b$.
add a comment |Â
up vote
0
down vote
up vote
0
down vote
In general, if $d=gcd(a,b)$, then any integer of the form $nd$ for some integer $n$ can be expressed as a linear combination of $a$ and $b$. This is because we can write $a=da_1$ and $b=db_1$ for integers $a_1,b_1$ so that $gcd(a_1,b_1)=1$. By the euclidean algorithm this leads us to the fact that there exists $k_1,k_2$ such that
$$1=k_1a_1+k_2b_1$$
for all $a_1,b_1$. Multiplying both sides of the equation by $nd$, we get
$$nd=nk_1(da_1)+nk_2(db_1)=nk_1a+nk_2b$$
Which gives us a way to find anything of the form $nd$ as a linear combination of $a,b$.
In general, if $d=gcd(a,b)$, then any integer of the form $nd$ for some integer $n$ can be expressed as a linear combination of $a$ and $b$. This is because we can write $a=da_1$ and $b=db_1$ for integers $a_1,b_1$ so that $gcd(a_1,b_1)=1$. By the euclidean algorithm this leads us to the fact that there exists $k_1,k_2$ such that
$$1=k_1a_1+k_2b_1$$
for all $a_1,b_1$. Multiplying both sides of the equation by $nd$, we get
$$nd=nk_1(da_1)+nk_2(db_1)=nk_1a+nk_2b$$
Which gives us a way to find anything of the form $nd$ as a linear combination of $a,b$.
answered 19 mins ago
user496634
8661110
8661110
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Yes, that is right
â DonAntonio
34 mins ago
If $gcd(a,b) = 1$ then there are $c,d $ such that $ac+bd = 1$ and hence if $p$ is an integer we can write $p = (cp)a + (dp)b$.
â copper.hat
32 mins ago