Math Is Fun Forum

  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#1 Re: Exercises » Group Theory » 2023-02-08 22:11:36

7. Show that if abab = aabb, then it must be that ab = ba.

a' is inverse for a
b' is inverse for b
e is identity

abab = aabb
(abab)b' = (aabb)b'
(aba)(bb') = (aab)(bb')
(aba)e = (aab)e
aba = aab
a'(aba) = a'(aab)
(a'a)(ba) = (a'a)(ab)
e(ba) = e(ab)
ba = ab
ab = ba

#2 Re: Exercises » Group Theory » 2023-02-08 18:57:37

7. Show that if abab = aabb, then it must be that ab = ba.

Stars (operation symbols) are missed in between these letters.

#3 Re: Exercises » Group Theory » 2023-02-08 16:39:17

Show that a group can have one and only one identity e. There should not be 2 different identities e1 and e2 in the same group, when e1 does not equal e2.

Board footer

Powered by FluxBB