Proving $(a b)(c d)=(a b c)(b c d)$ [closed]
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I was reading a book in Group theory and they said that $(a, b)(c, d)=(a, b, c)(b, c, d),$ but they did not prove it, for some reason (maybe it's too obvious but i can't seem to see it).
How to formally prove that $$(a, b)(c, d)=(a, b, c)(b, c, d),$$ when $(a, b),(c, d),(a, b, c),(b, c, d)in S_n$ so $ngeq 3$.
group-theory permutations symmetric-groups
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closed as off-topic by amWhy, Paul Frost, Chris Godsil, KReiser, M. Vinay Jan 2 at 7:52
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – amWhy, Paul Frost, Chris Godsil, KReiser, M. Vinay
If this question can be reworded to fit the rules in the help center, please edit the question.
add a comment |
$begingroup$
I was reading a book in Group theory and they said that $(a, b)(c, d)=(a, b, c)(b, c, d),$ but they did not prove it, for some reason (maybe it's too obvious but i can't seem to see it).
How to formally prove that $$(a, b)(c, d)=(a, b, c)(b, c, d),$$ when $(a, b),(c, d),(a, b, c),(b, c, d)in S_n$ so $ngeq 3$.
group-theory permutations symmetric-groups
$endgroup$
closed as off-topic by amWhy, Paul Frost, Chris Godsil, KReiser, M. Vinay Jan 2 at 7:52
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – amWhy, Paul Frost, Chris Godsil, KReiser, M. Vinay
If this question can be reworded to fit the rules in the help center, please edit the question.
$begingroup$
Please specify which book you are reading, using an edit.
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– Shaun
Jan 1 at 19:24
2
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it is obvious if one knows the rules to do it: form right to left. THat's all.
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– DonAntonio
Jan 1 at 19:26
add a comment |
$begingroup$
I was reading a book in Group theory and they said that $(a, b)(c, d)=(a, b, c)(b, c, d),$ but they did not prove it, for some reason (maybe it's too obvious but i can't seem to see it).
How to formally prove that $$(a, b)(c, d)=(a, b, c)(b, c, d),$$ when $(a, b),(c, d),(a, b, c),(b, c, d)in S_n$ so $ngeq 3$.
group-theory permutations symmetric-groups
$endgroup$
I was reading a book in Group theory and they said that $(a, b)(c, d)=(a, b, c)(b, c, d),$ but they did not prove it, for some reason (maybe it's too obvious but i can't seem to see it).
How to formally prove that $$(a, b)(c, d)=(a, b, c)(b, c, d),$$ when $(a, b),(c, d),(a, b, c),(b, c, d)in S_n$ so $ngeq 3$.
group-theory permutations symmetric-groups
group-theory permutations symmetric-groups
edited Jan 1 at 19:41
Shaun
8,818113681
8,818113681
asked Jan 1 at 19:22
vesiivesii
886
886
closed as off-topic by amWhy, Paul Frost, Chris Godsil, KReiser, M. Vinay Jan 2 at 7:52
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – amWhy, Paul Frost, Chris Godsil, KReiser, M. Vinay
If this question can be reworded to fit the rules in the help center, please edit the question.
closed as off-topic by amWhy, Paul Frost, Chris Godsil, KReiser, M. Vinay Jan 2 at 7:52
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – amWhy, Paul Frost, Chris Godsil, KReiser, M. Vinay
If this question can be reworded to fit the rules in the help center, please edit the question.
$begingroup$
Please specify which book you are reading, using an edit.
$endgroup$
– Shaun
Jan 1 at 19:24
2
$begingroup$
it is obvious if one knows the rules to do it: form right to left. THat's all.
$endgroup$
– DonAntonio
Jan 1 at 19:26
add a comment |
$begingroup$
Please specify which book you are reading, using an edit.
$endgroup$
– Shaun
Jan 1 at 19:24
2
$begingroup$
it is obvious if one knows the rules to do it: form right to left. THat's all.
$endgroup$
– DonAntonio
Jan 1 at 19:26
$begingroup$
Please specify which book you are reading, using an edit.
$endgroup$
– Shaun
Jan 1 at 19:24
$begingroup$
Please specify which book you are reading, using an edit.
$endgroup$
– Shaun
Jan 1 at 19:24
2
2
$begingroup$
it is obvious if one knows the rules to do it: form right to left. THat's all.
$endgroup$
– DonAntonio
Jan 1 at 19:26
$begingroup$
it is obvious if one knows the rules to do it: form right to left. THat's all.
$endgroup$
– DonAntonio
Jan 1 at 19:26
add a comment |
3 Answers
3
active
oldest
votes
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Hint:
This seems to two products of cycles. The product corresponds to composition, and goes from right to left. So the product of the two $3$-cycles on the right the results in
$$begin{cases}
a mapsto a mapsto b \
bmapsto cmapsto a \
cmapsto dmapsto d \
dmapsto bmapsto c
end{cases}quad text{which is }; (a,b)(c,d).$$
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add a comment |
$begingroup$
Hint:
Recall that a permutation is a bijection to & from a (finite) set. What do $a,b,c,$ and $d$ map to under $(a, b)(c, d)$ and under $(a, b, c)(b, c, d)$?
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add a comment |
$begingroup$
They both equate to the permutation: $$begin{pmatrix} a& b & c & d\
b & a & d&cend{pmatrix}.$$
$endgroup$
add a comment |
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Hint:
This seems to two products of cycles. The product corresponds to composition, and goes from right to left. So the product of the two $3$-cycles on the right the results in
$$begin{cases}
a mapsto a mapsto b \
bmapsto cmapsto a \
cmapsto dmapsto d \
dmapsto bmapsto c
end{cases}quad text{which is }; (a,b)(c,d).$$
$endgroup$
add a comment |
$begingroup$
Hint:
This seems to two products of cycles. The product corresponds to composition, and goes from right to left. So the product of the two $3$-cycles on the right the results in
$$begin{cases}
a mapsto a mapsto b \
bmapsto cmapsto a \
cmapsto dmapsto d \
dmapsto bmapsto c
end{cases}quad text{which is }; (a,b)(c,d).$$
$endgroup$
add a comment |
$begingroup$
Hint:
This seems to two products of cycles. The product corresponds to composition, and goes from right to left. So the product of the two $3$-cycles on the right the results in
$$begin{cases}
a mapsto a mapsto b \
bmapsto cmapsto a \
cmapsto dmapsto d \
dmapsto bmapsto c
end{cases}quad text{which is }; (a,b)(c,d).$$
$endgroup$
Hint:
This seems to two products of cycles. The product corresponds to composition, and goes from right to left. So the product of the two $3$-cycles on the right the results in
$$begin{cases}
a mapsto a mapsto b \
bmapsto cmapsto a \
cmapsto dmapsto d \
dmapsto bmapsto c
end{cases}quad text{which is }; (a,b)(c,d).$$
answered Jan 1 at 19:39
BernardBernard
119k639112
119k639112
add a comment |
add a comment |
$begingroup$
Hint:
Recall that a permutation is a bijection to & from a (finite) set. What do $a,b,c,$ and $d$ map to under $(a, b)(c, d)$ and under $(a, b, c)(b, c, d)$?
$endgroup$
add a comment |
$begingroup$
Hint:
Recall that a permutation is a bijection to & from a (finite) set. What do $a,b,c,$ and $d$ map to under $(a, b)(c, d)$ and under $(a, b, c)(b, c, d)$?
$endgroup$
add a comment |
$begingroup$
Hint:
Recall that a permutation is a bijection to & from a (finite) set. What do $a,b,c,$ and $d$ map to under $(a, b)(c, d)$ and under $(a, b, c)(b, c, d)$?
$endgroup$
Hint:
Recall that a permutation is a bijection to & from a (finite) set. What do $a,b,c,$ and $d$ map to under $(a, b)(c, d)$ and under $(a, b, c)(b, c, d)$?
edited Jan 1 at 20:10
answered Jan 1 at 19:28
ShaunShaun
8,818113681
8,818113681
add a comment |
add a comment |
$begingroup$
They both equate to the permutation: $$begin{pmatrix} a& b & c & d\
b & a & d&cend{pmatrix}.$$
$endgroup$
add a comment |
$begingroup$
They both equate to the permutation: $$begin{pmatrix} a& b & c & d\
b & a & d&cend{pmatrix}.$$
$endgroup$
add a comment |
$begingroup$
They both equate to the permutation: $$begin{pmatrix} a& b & c & d\
b & a & d&cend{pmatrix}.$$
$endgroup$
They both equate to the permutation: $$begin{pmatrix} a& b & c & d\
b & a & d&cend{pmatrix}.$$
edited Jan 1 at 20:11
Shaun
8,818113681
8,818113681
answered Jan 1 at 19:47
Chris CusterChris Custer
11.2k3824
11.2k3824
add a comment |
add a comment |
$begingroup$
Please specify which book you are reading, using an edit.
$endgroup$
– Shaun
Jan 1 at 19:24
2
$begingroup$
it is obvious if one knows the rules to do it: form right to left. THat's all.
$endgroup$
– DonAntonio
Jan 1 at 19:26