Degree or valency of a Cayley graph
Let $G$ be a group and $S subseteq G$ be a generating set of $G$.
The Cayley digraph of $G$ with respect
to $S$, $X=overrightarrow {operatorname{Cay}}(G, S)$ is a graph whose vertices are the elements of $G$ and there is an edge from $g$ to $gs$
whenever $g in G$ and $s in S$.
The Cayley graph, $X = operatorname{Cay}(G, S)$ is the undirected graph whose vertices
are the elements of $G$ and there is an edge from $g$ to $gs$ and from $g$ to $gs^{-1}$ whenever $g in G$ and $s in S$.
In a group, an element of order $2$ is known as an "involution". i.e. a non-identity element
whose square is the identity element.
So by thinking about the above definitions I have written the following about the degree of a Cayley graph, $X=operatorname{Cay}(G,S)$ of a group $G$, with respect to a generator set $S$:
"$deg(X)= 2vert S vert $, if $S$ has elements which are not involutions"
I would like to know whether above sentence is correct. Is it ok, to mention as "$S$ has elements which are not involutions"?
abstract-algebra group-theory graph-theory finite-groups cayley-graphs
add a comment |
Let $G$ be a group and $S subseteq G$ be a generating set of $G$.
The Cayley digraph of $G$ with respect
to $S$, $X=overrightarrow {operatorname{Cay}}(G, S)$ is a graph whose vertices are the elements of $G$ and there is an edge from $g$ to $gs$
whenever $g in G$ and $s in S$.
The Cayley graph, $X = operatorname{Cay}(G, S)$ is the undirected graph whose vertices
are the elements of $G$ and there is an edge from $g$ to $gs$ and from $g$ to $gs^{-1}$ whenever $g in G$ and $s in S$.
In a group, an element of order $2$ is known as an "involution". i.e. a non-identity element
whose square is the identity element.
So by thinking about the above definitions I have written the following about the degree of a Cayley graph, $X=operatorname{Cay}(G,S)$ of a group $G$, with respect to a generator set $S$:
"$deg(X)= 2vert S vert $, if $S$ has elements which are not involutions"
I would like to know whether above sentence is correct. Is it ok, to mention as "$S$ has elements which are not involutions"?
abstract-algebra group-theory graph-theory finite-groups cayley-graphs
You asked this in the group theory chatroom. However, in order to avoid downvotes on this question or having it closed, please edit it to include more context, such as why the question is interesting to you, where it arose, and what you have done to solve it yourself :)
– Shaun
Dec 26 '18 at 19:29
1
Ok, thanks @Shaun :) :)
– Buddhini Angelika
Dec 27 '18 at 8:53
After you ask a question here, if you get an acceptable answer, you should "accept" the answer by clicking the check mark $checkmark$ next to it. This scores points for you and for the person who answered your question. You can find out more about accepting answers here: How do I accept an answer?, Why should we accept answers?, What should I do if someone answers my question?.
– Shaun
Dec 27 '18 at 9:12
Thank you @Shaun :) :)
– Buddhini Angelika
Dec 28 '18 at 10:46
add a comment |
Let $G$ be a group and $S subseteq G$ be a generating set of $G$.
The Cayley digraph of $G$ with respect
to $S$, $X=overrightarrow {operatorname{Cay}}(G, S)$ is a graph whose vertices are the elements of $G$ and there is an edge from $g$ to $gs$
whenever $g in G$ and $s in S$.
The Cayley graph, $X = operatorname{Cay}(G, S)$ is the undirected graph whose vertices
are the elements of $G$ and there is an edge from $g$ to $gs$ and from $g$ to $gs^{-1}$ whenever $g in G$ and $s in S$.
In a group, an element of order $2$ is known as an "involution". i.e. a non-identity element
whose square is the identity element.
So by thinking about the above definitions I have written the following about the degree of a Cayley graph, $X=operatorname{Cay}(G,S)$ of a group $G$, with respect to a generator set $S$:
"$deg(X)= 2vert S vert $, if $S$ has elements which are not involutions"
I would like to know whether above sentence is correct. Is it ok, to mention as "$S$ has elements which are not involutions"?
abstract-algebra group-theory graph-theory finite-groups cayley-graphs
Let $G$ be a group and $S subseteq G$ be a generating set of $G$.
The Cayley digraph of $G$ with respect
to $S$, $X=overrightarrow {operatorname{Cay}}(G, S)$ is a graph whose vertices are the elements of $G$ and there is an edge from $g$ to $gs$
whenever $g in G$ and $s in S$.
The Cayley graph, $X = operatorname{Cay}(G, S)$ is the undirected graph whose vertices
are the elements of $G$ and there is an edge from $g$ to $gs$ and from $g$ to $gs^{-1}$ whenever $g in G$ and $s in S$.
In a group, an element of order $2$ is known as an "involution". i.e. a non-identity element
whose square is the identity element.
So by thinking about the above definitions I have written the following about the degree of a Cayley graph, $X=operatorname{Cay}(G,S)$ of a group $G$, with respect to a generator set $S$:
"$deg(X)= 2vert S vert $, if $S$ has elements which are not involutions"
I would like to know whether above sentence is correct. Is it ok, to mention as "$S$ has elements which are not involutions"?
abstract-algebra group-theory graph-theory finite-groups cayley-graphs
abstract-algebra group-theory graph-theory finite-groups cayley-graphs
edited Dec 27 '18 at 9:13
Shaun
8,711113680
8,711113680
asked Dec 26 '18 at 17:36
Buddhini Angelika
15710
15710
You asked this in the group theory chatroom. However, in order to avoid downvotes on this question or having it closed, please edit it to include more context, such as why the question is interesting to you, where it arose, and what you have done to solve it yourself :)
– Shaun
Dec 26 '18 at 19:29
1
Ok, thanks @Shaun :) :)
– Buddhini Angelika
Dec 27 '18 at 8:53
After you ask a question here, if you get an acceptable answer, you should "accept" the answer by clicking the check mark $checkmark$ next to it. This scores points for you and for the person who answered your question. You can find out more about accepting answers here: How do I accept an answer?, Why should we accept answers?, What should I do if someone answers my question?.
– Shaun
Dec 27 '18 at 9:12
Thank you @Shaun :) :)
– Buddhini Angelika
Dec 28 '18 at 10:46
add a comment |
You asked this in the group theory chatroom. However, in order to avoid downvotes on this question or having it closed, please edit it to include more context, such as why the question is interesting to you, where it arose, and what you have done to solve it yourself :)
– Shaun
Dec 26 '18 at 19:29
1
Ok, thanks @Shaun :) :)
– Buddhini Angelika
Dec 27 '18 at 8:53
After you ask a question here, if you get an acceptable answer, you should "accept" the answer by clicking the check mark $checkmark$ next to it. This scores points for you and for the person who answered your question. You can find out more about accepting answers here: How do I accept an answer?, Why should we accept answers?, What should I do if someone answers my question?.
– Shaun
Dec 27 '18 at 9:12
Thank you @Shaun :) :)
– Buddhini Angelika
Dec 28 '18 at 10:46
You asked this in the group theory chatroom. However, in order to avoid downvotes on this question or having it closed, please edit it to include more context, such as why the question is interesting to you, where it arose, and what you have done to solve it yourself :)
– Shaun
Dec 26 '18 at 19:29
You asked this in the group theory chatroom. However, in order to avoid downvotes on this question or having it closed, please edit it to include more context, such as why the question is interesting to you, where it arose, and what you have done to solve it yourself :)
– Shaun
Dec 26 '18 at 19:29
1
1
Ok, thanks @Shaun :) :)
– Buddhini Angelika
Dec 27 '18 at 8:53
Ok, thanks @Shaun :) :)
– Buddhini Angelika
Dec 27 '18 at 8:53
After you ask a question here, if you get an acceptable answer, you should "accept" the answer by clicking the check mark $checkmark$ next to it. This scores points for you and for the person who answered your question. You can find out more about accepting answers here: How do I accept an answer?, Why should we accept answers?, What should I do if someone answers my question?.
– Shaun
Dec 27 '18 at 9:12
After you ask a question here, if you get an acceptable answer, you should "accept" the answer by clicking the check mark $checkmark$ next to it. This scores points for you and for the person who answered your question. You can find out more about accepting answers here: How do I accept an answer?, Why should we accept answers?, What should I do if someone answers my question?.
– Shaun
Dec 27 '18 at 9:12
Thank you @Shaun :) :)
– Buddhini Angelika
Dec 28 '18 at 10:46
Thank you @Shaun :) :)
– Buddhini Angelika
Dec 28 '18 at 10:46
add a comment |
1 Answer
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votes
The answer may depend on definitions of a Cayley graph and vertex degree. Namely, if we consider the directed Cayley graph then in-degree of its each vertex equals to its out-degree and equals to $|S|$. If we consider the undirected Cayley graph then we assume that $S$ is symmetric and without the identity ${e}$ and then degree of its each vertex equals $|S|$.
Thanks @AlexRavsky I have added more details to the question as instructed. Do you think it's correct to mention about involutions ?
– Buddhini Angelika
Dec 27 '18 at 8:35
@BuddhiniAngelika According to the given definition of ${operatorname{Cay}}(G, S)$ degree of any its vertex is $2|S|-|S_i|$, where $S_i={gin S: g$ is an involution$}$. In particular, if $S$ contains no involutions then degrere of each vertex of ${operatorname{Cay}}(G, S)$ is $2|S|$.
– Alex Ravsky
Dec 27 '18 at 8:55
1
Thank you very much @AlexRavsky
– Buddhini Angelika
Dec 28 '18 at 2:58
add a comment |
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1 Answer
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1 Answer
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The answer may depend on definitions of a Cayley graph and vertex degree. Namely, if we consider the directed Cayley graph then in-degree of its each vertex equals to its out-degree and equals to $|S|$. If we consider the undirected Cayley graph then we assume that $S$ is symmetric and without the identity ${e}$ and then degree of its each vertex equals $|S|$.
Thanks @AlexRavsky I have added more details to the question as instructed. Do you think it's correct to mention about involutions ?
– Buddhini Angelika
Dec 27 '18 at 8:35
@BuddhiniAngelika According to the given definition of ${operatorname{Cay}}(G, S)$ degree of any its vertex is $2|S|-|S_i|$, where $S_i={gin S: g$ is an involution$}$. In particular, if $S$ contains no involutions then degrere of each vertex of ${operatorname{Cay}}(G, S)$ is $2|S|$.
– Alex Ravsky
Dec 27 '18 at 8:55
1
Thank you very much @AlexRavsky
– Buddhini Angelika
Dec 28 '18 at 2:58
add a comment |
The answer may depend on definitions of a Cayley graph and vertex degree. Namely, if we consider the directed Cayley graph then in-degree of its each vertex equals to its out-degree and equals to $|S|$. If we consider the undirected Cayley graph then we assume that $S$ is symmetric and without the identity ${e}$ and then degree of its each vertex equals $|S|$.
Thanks @AlexRavsky I have added more details to the question as instructed. Do you think it's correct to mention about involutions ?
– Buddhini Angelika
Dec 27 '18 at 8:35
@BuddhiniAngelika According to the given definition of ${operatorname{Cay}}(G, S)$ degree of any its vertex is $2|S|-|S_i|$, where $S_i={gin S: g$ is an involution$}$. In particular, if $S$ contains no involutions then degrere of each vertex of ${operatorname{Cay}}(G, S)$ is $2|S|$.
– Alex Ravsky
Dec 27 '18 at 8:55
1
Thank you very much @AlexRavsky
– Buddhini Angelika
Dec 28 '18 at 2:58
add a comment |
The answer may depend on definitions of a Cayley graph and vertex degree. Namely, if we consider the directed Cayley graph then in-degree of its each vertex equals to its out-degree and equals to $|S|$. If we consider the undirected Cayley graph then we assume that $S$ is symmetric and without the identity ${e}$ and then degree of its each vertex equals $|S|$.
The answer may depend on definitions of a Cayley graph and vertex degree. Namely, if we consider the directed Cayley graph then in-degree of its each vertex equals to its out-degree and equals to $|S|$. If we consider the undirected Cayley graph then we assume that $S$ is symmetric and without the identity ${e}$ and then degree of its each vertex equals $|S|$.
answered Dec 26 '18 at 21:07
Alex Ravsky
39.2k32080
39.2k32080
Thanks @AlexRavsky I have added more details to the question as instructed. Do you think it's correct to mention about involutions ?
– Buddhini Angelika
Dec 27 '18 at 8:35
@BuddhiniAngelika According to the given definition of ${operatorname{Cay}}(G, S)$ degree of any its vertex is $2|S|-|S_i|$, where $S_i={gin S: g$ is an involution$}$. In particular, if $S$ contains no involutions then degrere of each vertex of ${operatorname{Cay}}(G, S)$ is $2|S|$.
– Alex Ravsky
Dec 27 '18 at 8:55
1
Thank you very much @AlexRavsky
– Buddhini Angelika
Dec 28 '18 at 2:58
add a comment |
Thanks @AlexRavsky I have added more details to the question as instructed. Do you think it's correct to mention about involutions ?
– Buddhini Angelika
Dec 27 '18 at 8:35
@BuddhiniAngelika According to the given definition of ${operatorname{Cay}}(G, S)$ degree of any its vertex is $2|S|-|S_i|$, where $S_i={gin S: g$ is an involution$}$. In particular, if $S$ contains no involutions then degrere of each vertex of ${operatorname{Cay}}(G, S)$ is $2|S|$.
– Alex Ravsky
Dec 27 '18 at 8:55
1
Thank you very much @AlexRavsky
– Buddhini Angelika
Dec 28 '18 at 2:58
Thanks @AlexRavsky I have added more details to the question as instructed. Do you think it's correct to mention about involutions ?
– Buddhini Angelika
Dec 27 '18 at 8:35
Thanks @AlexRavsky I have added more details to the question as instructed. Do you think it's correct to mention about involutions ?
– Buddhini Angelika
Dec 27 '18 at 8:35
@BuddhiniAngelika According to the given definition of ${operatorname{Cay}}(G, S)$ degree of any its vertex is $2|S|-|S_i|$, where $S_i={gin S: g$ is an involution$}$. In particular, if $S$ contains no involutions then degrere of each vertex of ${operatorname{Cay}}(G, S)$ is $2|S|$.
– Alex Ravsky
Dec 27 '18 at 8:55
@BuddhiniAngelika According to the given definition of ${operatorname{Cay}}(G, S)$ degree of any its vertex is $2|S|-|S_i|$, where $S_i={gin S: g$ is an involution$}$. In particular, if $S$ contains no involutions then degrere of each vertex of ${operatorname{Cay}}(G, S)$ is $2|S|$.
– Alex Ravsky
Dec 27 '18 at 8:55
1
1
Thank you very much @AlexRavsky
– Buddhini Angelika
Dec 28 '18 at 2:58
Thank you very much @AlexRavsky
– Buddhini Angelika
Dec 28 '18 at 2:58
add a comment |
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You asked this in the group theory chatroom. However, in order to avoid downvotes on this question or having it closed, please edit it to include more context, such as why the question is interesting to you, where it arose, and what you have done to solve it yourself :)
– Shaun
Dec 26 '18 at 19:29
1
Ok, thanks @Shaun :) :)
– Buddhini Angelika
Dec 27 '18 at 8:53
After you ask a question here, if you get an acceptable answer, you should "accept" the answer by clicking the check mark $checkmark$ next to it. This scores points for you and for the person who answered your question. You can find out more about accepting answers here: How do I accept an answer?, Why should we accept answers?, What should I do if someone answers my question?.
– Shaun
Dec 27 '18 at 9:12
Thank you @Shaun :) :)
– Buddhini Angelika
Dec 28 '18 at 10:46