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11ee1
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iam currently studying undergraduate abstract algebra and i have reached to the permutation group topic i understand every thing till now but iam having trouble understanding the proof of
"IF the identity permutation I of {1,2...n} is represented by m transpositions then m is even"
I understand that the identity permutation should fix all the number that u put in it so I(1)=1 I(2)=2 etc..
so the proof is by induction it start with n=2 so I is represented by (12)(12)(12)...
in which it is easy to see that m should be even since I keeps switching 1with 2 till they are in the same position they were in the beginning and (12) fixes all other numbers
but then how do u do the induction step??
I don't even understand how it would work for n=3 :( everything was flowing well but then iam stuck with this...if anyone can help me it would be really appreciated
"IF the identity permutation I of {1,2...n} is represented by m transpositions then m is even"
I understand that the identity permutation should fix all the number that u put in it so I(1)=1 I(2)=2 etc..
so the proof is by induction it start with n=2 so I is represented by (12)(12)(12)...
in which it is easy to see that m should be even since I keeps switching 1with 2 till they are in the same position they were in the beginning and (12) fixes all other numbers
but then how do u do the induction step??
I don't even understand how it would work for n=3 :( everything was flowing well but then iam stuck with this...if anyone can help me it would be really appreciated