Understanding an expression which related to full binary trees
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I am quite new to discrete mathematics. I was going through graph and found this expression which was for full binary tree, where $B_h$ represents graph i.e. full binary tree of length/ height h
$B_h := ([2]^{≤h}, {{u,ux} such that uepsilon [2]^{<h}, xepsilon [2]})$
I got confused here. what do $[2]^{≤h}$ and $[2]^{<h}$ mean here, i am quite certain that [2] means {1,2}. But that exponent on the set is quite not clear to me. does that mean cartesian product? I would be thankful for any kind of help. thanks!
discrete-mathematics elementary-set-theory graph-theory notation
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add a comment |
$begingroup$
I am quite new to discrete mathematics. I was going through graph and found this expression which was for full binary tree, where $B_h$ represents graph i.e. full binary tree of length/ height h
$B_h := ([2]^{≤h}, {{u,ux} such that uepsilon [2]^{<h}, xepsilon [2]})$
I got confused here. what do $[2]^{≤h}$ and $[2]^{<h}$ mean here, i am quite certain that [2] means {1,2}. But that exponent on the set is quite not clear to me. does that mean cartesian product? I would be thankful for any kind of help. thanks!
discrete-mathematics elementary-set-theory graph-theory notation
$endgroup$
$begingroup$
We can make educated guesses, but also you have some typos in your formula, and for a definitely correct answer you probably want to say something about where this expression comes from so that we have context.
$endgroup$
– Misha Lavrov
Jan 28 at 21:58
add a comment |
$begingroup$
I am quite new to discrete mathematics. I was going through graph and found this expression which was for full binary tree, where $B_h$ represents graph i.e. full binary tree of length/ height h
$B_h := ([2]^{≤h}, {{u,ux} such that uepsilon [2]^{<h}, xepsilon [2]})$
I got confused here. what do $[2]^{≤h}$ and $[2]^{<h}$ mean here, i am quite certain that [2] means {1,2}. But that exponent on the set is quite not clear to me. does that mean cartesian product? I would be thankful for any kind of help. thanks!
discrete-mathematics elementary-set-theory graph-theory notation
$endgroup$
I am quite new to discrete mathematics. I was going through graph and found this expression which was for full binary tree, where $B_h$ represents graph i.e. full binary tree of length/ height h
$B_h := ([2]^{≤h}, {{u,ux} such that uepsilon [2]^{<h}, xepsilon [2]})$
I got confused here. what do $[2]^{≤h}$ and $[2]^{<h}$ mean here, i am quite certain that [2] means {1,2}. But that exponent on the set is quite not clear to me. does that mean cartesian product? I would be thankful for any kind of help. thanks!
discrete-mathematics elementary-set-theory graph-theory notation
discrete-mathematics elementary-set-theory graph-theory notation
edited Jan 28 at 22:09
the hitchhiker
asked Jan 28 at 21:48


the hitchhikerthe hitchhiker
62
62
$begingroup$
We can make educated guesses, but also you have some typos in your formula, and for a definitely correct answer you probably want to say something about where this expression comes from so that we have context.
$endgroup$
– Misha Lavrov
Jan 28 at 21:58
add a comment |
$begingroup$
We can make educated guesses, but also you have some typos in your formula, and for a definitely correct answer you probably want to say something about where this expression comes from so that we have context.
$endgroup$
– Misha Lavrov
Jan 28 at 21:58
$begingroup$
We can make educated guesses, but also you have some typos in your formula, and for a definitely correct answer you probably want to say something about where this expression comes from so that we have context.
$endgroup$
– Misha Lavrov
Jan 28 at 21:58
$begingroup$
We can make educated guesses, but also you have some typos in your formula, and for a definitely correct answer you probably want to say something about where this expression comes from so that we have context.
$endgroup$
– Misha Lavrov
Jan 28 at 21:58
add a comment |
1 Answer
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If you will permit, I am more comfortable thinking of $[2]$ as ${0,1}$.
$[2]^h$ is the Cartesian product of $[2]$ with itself $[h]$ times:
$$
[2]^h=[2]times[2]timesdotstimes[2]cong{(b_1,b_2,dots,b_h)mid b_iin [2]text{ for }1le ile h}
$$
In other words, $[2]^h$ consists of binary sequences of length $h$. Then,
$$
[2]^{le h}=[2]^0cup [2]^1cup dotscup [2]^h
$$
is the set of binary sequences of length at most $h$. That is, $2^{le [h]}$ is not a Cartesian product, but a union of Cartesian products. You can probably imagine now what $[2]^{<h}$ is; it consists of binary sequences whose lengths are strictly less than $h$.
The set of edges is of the form ${u,ux}$, where $u$ is a binary sequence of length less than $h$, and $xin {0,1}$. The multiplication here is concatenation. For example, letting $u=(0,1,0)$, and $x=0$, there is an edge between $(0,1,0)$ and $(0,1,0,0)$; we add a $0$ to the end of $u$ to get its neighbor.
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$begingroup$
If you will permit, I am more comfortable thinking of $[2]$ as ${0,1}$.
$[2]^h$ is the Cartesian product of $[2]$ with itself $[h]$ times:
$$
[2]^h=[2]times[2]timesdotstimes[2]cong{(b_1,b_2,dots,b_h)mid b_iin [2]text{ for }1le ile h}
$$
In other words, $[2]^h$ consists of binary sequences of length $h$. Then,
$$
[2]^{le h}=[2]^0cup [2]^1cup dotscup [2]^h
$$
is the set of binary sequences of length at most $h$. That is, $2^{le [h]}$ is not a Cartesian product, but a union of Cartesian products. You can probably imagine now what $[2]^{<h}$ is; it consists of binary sequences whose lengths are strictly less than $h$.
The set of edges is of the form ${u,ux}$, where $u$ is a binary sequence of length less than $h$, and $xin {0,1}$. The multiplication here is concatenation. For example, letting $u=(0,1,0)$, and $x=0$, there is an edge between $(0,1,0)$ and $(0,1,0,0)$; we add a $0$ to the end of $u$ to get its neighbor.
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add a comment |
$begingroup$
If you will permit, I am more comfortable thinking of $[2]$ as ${0,1}$.
$[2]^h$ is the Cartesian product of $[2]$ with itself $[h]$ times:
$$
[2]^h=[2]times[2]timesdotstimes[2]cong{(b_1,b_2,dots,b_h)mid b_iin [2]text{ for }1le ile h}
$$
In other words, $[2]^h$ consists of binary sequences of length $h$. Then,
$$
[2]^{le h}=[2]^0cup [2]^1cup dotscup [2]^h
$$
is the set of binary sequences of length at most $h$. That is, $2^{le [h]}$ is not a Cartesian product, but a union of Cartesian products. You can probably imagine now what $[2]^{<h}$ is; it consists of binary sequences whose lengths are strictly less than $h$.
The set of edges is of the form ${u,ux}$, where $u$ is a binary sequence of length less than $h$, and $xin {0,1}$. The multiplication here is concatenation. For example, letting $u=(0,1,0)$, and $x=0$, there is an edge between $(0,1,0)$ and $(0,1,0,0)$; we add a $0$ to the end of $u$ to get its neighbor.
$endgroup$
add a comment |
$begingroup$
If you will permit, I am more comfortable thinking of $[2]$ as ${0,1}$.
$[2]^h$ is the Cartesian product of $[2]$ with itself $[h]$ times:
$$
[2]^h=[2]times[2]timesdotstimes[2]cong{(b_1,b_2,dots,b_h)mid b_iin [2]text{ for }1le ile h}
$$
In other words, $[2]^h$ consists of binary sequences of length $h$. Then,
$$
[2]^{le h}=[2]^0cup [2]^1cup dotscup [2]^h
$$
is the set of binary sequences of length at most $h$. That is, $2^{le [h]}$ is not a Cartesian product, but a union of Cartesian products. You can probably imagine now what $[2]^{<h}$ is; it consists of binary sequences whose lengths are strictly less than $h$.
The set of edges is of the form ${u,ux}$, where $u$ is a binary sequence of length less than $h$, and $xin {0,1}$. The multiplication here is concatenation. For example, letting $u=(0,1,0)$, and $x=0$, there is an edge between $(0,1,0)$ and $(0,1,0,0)$; we add a $0$ to the end of $u$ to get its neighbor.
$endgroup$
If you will permit, I am more comfortable thinking of $[2]$ as ${0,1}$.
$[2]^h$ is the Cartesian product of $[2]$ with itself $[h]$ times:
$$
[2]^h=[2]times[2]timesdotstimes[2]cong{(b_1,b_2,dots,b_h)mid b_iin [2]text{ for }1le ile h}
$$
In other words, $[2]^h$ consists of binary sequences of length $h$. Then,
$$
[2]^{le h}=[2]^0cup [2]^1cup dotscup [2]^h
$$
is the set of binary sequences of length at most $h$. That is, $2^{le [h]}$ is not a Cartesian product, but a union of Cartesian products. You can probably imagine now what $[2]^{<h}$ is; it consists of binary sequences whose lengths are strictly less than $h$.
The set of edges is of the form ${u,ux}$, where $u$ is a binary sequence of length less than $h$, and $xin {0,1}$. The multiplication here is concatenation. For example, letting $u=(0,1,0)$, and $x=0$, there is an edge between $(0,1,0)$ and $(0,1,0,0)$; we add a $0$ to the end of $u$ to get its neighbor.
edited Jan 29 at 4:30
answered Jan 29 at 3:14


Mike EarnestMike Earnest
26.2k22151
26.2k22151
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$begingroup$
We can make educated guesses, but also you have some typos in your formula, and for a definitely correct answer you probably want to say something about where this expression comes from so that we have context.
$endgroup$
– Misha Lavrov
Jan 28 at 21:58