Ask your own question, for FREE!
Mathematics 7 Online
OpenStudy (anonymous):

question on groups and symmetries please helpp

OpenStudy (anonymous):

OpenStudy (anonymous):

i need help on question 1 in that picture pleaseee

OpenStudy (anonymous):

@amistre64

OpenStudy (anonymous):

@KingGeorge

OpenStudy (anonymous):

@satellite73

OpenStudy (amistre64):

just running thru the rolodex eh ....

OpenStudy (anonymous):

noo, these tutors are pro in this course and helped me before

OpenStudy (amistre64):

eww! i cant even begin to read that stuff .... im out :)

OpenStudy (anonymous):

lol its okay :P

OpenStudy (anonymous):

@TuringTest

OpenStudy (anonymous):

soo far i found the order of all elements in A4

OpenStudy (anonymous):

YESS kinggeorge heyy

OpenStudy (anonymous):

i got the the order of (1) = 1 the order of (13)(24) = (14)(23) = 2

OpenStudy (kinggeorge):

So you're having trouble with the first problem?

OpenStudy (anonymous):

yeah and the order of (123) = (243) = (142) = 3 and the order of (134) = 4 and i still am doing the 9, 10 , 11 , 12 orders and doing it but i dont know how to map it

OpenStudy (anonymous):

like you said map it to Z6 but Z6 = {1, 2, 3, 4, 5} i didnt get how you got the order of 2 to be 3 as well

OpenStudy (kinggeorge):

Wait, I was using \(\mathbb{Z}_6=\{\{0,1,2,3,4,5\}, +_6\}\) Where \(+_6\) stands for addition modulo 6.

OpenStudy (anonymous):

yeah thats what we have to use

OpenStudy (anonymous):

yeah sorry i forgot the 0

OpenStudy (kinggeorge):

Well then \(|2|=3\) since \(2+2+2\equiv0\pmod{6}\).

OpenStudy (anonymous):

oo okay

OpenStudy (anonymous):

the order of 1is just 6, order of 3 is just 2

OpenStudy (anonymous):

whats the order of 0, 4, and 5

OpenStudy (kinggeorge):

The order of 0 is 1 since it's the identity, \(|4|=3\), and \(|5|=6\).

OpenStudy (anonymous):

hmm okay alright just give me a second let me map it to them

OpenStudy (anonymous):

and you also said it shoulnt be the same as the mapping before

OpenStudy (kinggeorge):

I'm not entirely sure what I meant by that statement. Show ,e what mapping you end up with, and we'll see where to go from there.

OpenStudy (anonymous):

alright should i list it for all 12 elements?

OpenStudy (kinggeorge):

Yes please.

OpenStudy (anonymous):

ooo and by the way what is (2)(2) is it just e

OpenStudy (kinggeorge):

I believe that would just be e.

OpenStudy (anonymous):

ok so i got

OpenStudy (anonymous):

(1) --> 0 (12)(34) = (13)(24) = (14)(23) --> 2 (123) = (243) = (142) --> 3 and i cant list the other elements because the order of (134) = (132) = (143) = (234) = (124) = 4 and there is no element in Z_6 that has order 4

OpenStudy (anonymous):

ok wait i just messed it up

OpenStudy (anonymous):

(1) --> 0 (12)(34) = (13)(24) = (14)(23) --> 3 (123) = (243) = (142) --> 2 and i cant list the other elements because the order of (134) = (132) = (143) = (234) = (124) = 4 and there is no element in Z_6 that has order 4

OpenStudy (kinggeorge):

So first, let's make a complete list of all the elements in \(A_4\). \[A_4=\left\{\begin{matrix}e,(12)(34),(13)(24),(14)(23),\\(123),(234),(134),(124),\\(132),(243),(143),(142)\end{matrix}\right\}\]Every single element in the top row is mapped to 0 since they're in the kernel. The other elements must be mapped to some number that has order 2.

OpenStudy (kinggeorge):

Thus, start like this\[\begin{align} e,(12)(34),(13)(24),(14)(23)&\longmapsto 0 \\(123)&\longmapsto2\\(132)&\longmapsto4\end{align}\]After this, we need to be careful that we preserve the homomorphism property I.e.\(\varphi(gh)=\varphi(g)\varphi(h)\).

OpenStudy (anonymous):

yes i noticed you know the other elements that i didnt include i was looking at your message if you square them i get them to go to 4

OpenStudy (kinggeorge):

Now look at \((123)(234)\). This is \((12)(34)\). So \(2+\varphi((234))=0\). This means that \[(234)\longmapsto4\]and\[(243)\longmapsto2\]

OpenStudy (kinggeorge):

In case it wasn't clear, \(2+\varphi((234))=0\) since \((12)(34)\) is in the kernel.

OpenStudy (anonymous):

wohh

OpenStudy (kinggeorge):

We continue to check similar things.\[(123)(134)=(234)\implies(134)\longmapsto2\]which then implies \[(143)\longmapsto4\]

OpenStudy (anonymous):

ok just one minute you know your fourth last post from right now you said (12)(34) --> 0 but the order of (12)(34) = 2 and the order of 0 is 1?

OpenStudy (kinggeorge):

\[(123)(124)=(13)(24)\implies(124)\longmapsto4\]and finally\[(142)\longmapsto2\] To answer your question, it's correct that the order of \((12)(34)\) in \(A_4\) is 2, but since it's defined to be part of the kernel, it must be that \[(12)(34)\longmapsto0\]By the definition of the kernel.

OpenStudy (anonymous):

alright and you know how you said (123) --> 2 should i list all of them like (123), (243), (142) --> 2 or it doesnt matter

OpenStudy (anonymous):

ok i am actually sorry this is so much to take in. Is there a reason why we are only using those permuations and not all of them?

OpenStudy (kinggeorge):

You should list it all out. So in total, you should get \[\{e,(12)(23),(13)(24),(14)(23)\}\longmapsto0\]\[\{(123),(134),(142),(243)\}\longmapsto2\]\[\{(132),(143),(124),(234)\}\longmapsto4\] We're using these permutations because these are all of the elements of \(A_4\).

OpenStudy (anonymous):

ok alright makes sense and that is our homomorphism then

OpenStudy (kinggeorge):

that should be the homomorphism.

OpenStudy (anonymous):

ok awesome makes sense to me

OpenStudy (anonymous):

should i ask the other question same on here or make a new post?

OpenStudy (kinggeorge):

A new post would be better.

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!