00:01
To prove the stat with the operation in the group, we need to verify these three axiens.
00:08
First, the operation is associative.
00:13
So we compute x, operate y, and then operate z.
00:20
We give this result.
00:24
And we can also compute x operate parasitis, y, operate z.
00:31
After simplification, we get this.
00:36
Note that these two expressions are the same, and hence the operation is associative.
00:47
Next, we want to find the identity.
00:53
So x operate the identity equals x plus e over xe plus 1.
01:05
And this should equal x.
01:08
We use this equation to solve for the identity e.
01:16
We multiply both sides by xe plus 1, and then we subtract x from both sides.
01:36
To guarantee this equation, hold, e must equal 0...