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Sep 17, 2023 at 16:14 vote accept YkMz
Sep 17, 2023 at 10:00 comment added YkMz I think I understand now. The reason why I misunderstood is that I thought $X_1X_2X_3$ as an element in $E''$ is given by a $\textit{left}$ multiplication of $X_1X_2X_3$ in $E''$. In order for $X_1X_2X_3$ to be a center in $E''$, I should have thought $X_1X_2X_3$ as an element in $E''$ is given by a $\textit{right} $ multiplication of $X_1X_2X_3$ in $E''$. This is what you wanted to tell me, isn't it ?
Sep 16, 2023 at 22:34 comment added Dave Benson Did you ever sort this out in your own mind? Did you want accept my answer, or are you still confused?
Sep 10, 2023 at 8:48 comment added Dave Benson I think that may be the source of your confusion about left and right multiplications.
Sep 10, 2023 at 8:38 comment added YkMz Perhaps, have I misunderstood how $E_0'$ is embedded in $E''$ ?
Sep 10, 2023 at 8:23 comment added Dave Benson Here's another way of putting it. Although left multiplication by $X_1X_2X_3$ is an endomorphism of $E'(1)$, it's not the endomorphism you need. What you need is the endomorphism $X_1X_2X_3$ of $E'$, conjugated by the isomorphism between $E'$ and $E'(1)$ given by multiplication by $x_0$.
Sep 10, 2023 at 8:20 comment added YkMz I apologize for the inconvenience. Is what I wrote in Edit wrong?
Sep 10, 2023 at 8:03 comment added Dave Benson Read my edited answer, and then play with the matrices.
Sep 10, 2023 at 8:02 comment added YkMz I am so sorry. I am confused and still don't understand.
Sep 10, 2023 at 6:21 history edited YkMz CC BY-SA 4.0
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Sep 9, 2023 at 0:53 history edited YkMz CC BY-SA 4.0
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Sep 8, 2023 at 9:12 history edited YkMz CC BY-SA 4.0
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Sep 8, 2023 at 5:51 history edited YkMz CC BY-SA 4.0
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Sep 8, 2023 at 3:55 history edited YkMz CC BY-SA 4.0
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Sep 8, 2023 at 3:47 history edited YkMz CC BY-SA 4.0
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Sep 8, 2023 at 0:42 history edited YkMz CC BY-SA 4.0
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Sep 8, 2023 at 0:18 history edited YkMz CC BY-SA 4.0
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Sep 7, 2023 at 14:18 answer added Dave Benson timeline score: 8
Sep 7, 2023 at 13:59 history edited YkMz CC BY-SA 4.0
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Sep 7, 2023 at 13:22 comment added YkMz Thank you very much for the comment. You mean that $ (X_1X_2X_3) \begin{pmatrix} 0 & x_0 \\ 0 & 0 \end{pmatrix} = \begin{pmatrix} 0 & x_0 \\ 0 & 0 \end{pmatrix} (X_1X_2X_3) $ in $E''$ ?
Sep 7, 2023 at 13:06 comment added Dave Benson I'm not sure, but your endomorphism $\left(\begin{smallmatrix} 0 & x_0 \\ 0 & 0\end{smallmatrix}\right)$ is probably right multiplication by this element, and so it commutes with left multiplication by $X_1X_2X_3$. Could this be the explanation?
Sep 7, 2023 at 12:40 history edited YkMz CC BY-SA 4.0
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Sep 7, 2023 at 12:09 history asked YkMz CC BY-SA 4.0