- #36

#### SammyS

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(I changed that toLauren1234 said:Hi this wasn’t the case. I changed it to add the image of my working so far under the original question but have come back to see nothings there.Math_QED said:I might be and I apologise to the OP if I'm wrong. I'm here since the beginning of the thread and yes, the post was edited. In the beginning it contained an image. Last time I looked it said the top post was edited around 7pm (several hours after the thread was created).

. . .I’ll edit it back in now!Sorry for any issues

**bold face**for emphasis.)

This thread continues to suffer for lack of a problem statement. (There's not even a poor problem statement.) I have continued the search for one ... in vain.

It seems that perhaps @Lauren1234 has not been able to edit the Original Post in this thread. This is very possible.

I have also searched for any image uploaded (as well as being still available) during the time span in question. None of the images I found was relevant.

In going over this thread quite a few times, I think I get the gist of it. It seems that both @Math_QED and @PeroK read this thread in its original form.

It seems that ##P## is a group. The elements of the group are matrices of the form: ##\displaystyle

\begin{pmatrix}

a & b & c \\

0 & d & e \\

0 & f & g

\end{pmatrix} ## . The group operation is matrix multiplication.

Since this is formally a group, each element must have an inverse, thus for such such matrix to be in the group, it must be invertible. Therefore, the determinant of any matrix in this group is nonzero. (This says something about ##a## as well as about the relationship between ##d,\ e,\ f, \text{and } g## ).

The rest is sort of clear.

Show that this group in non-abelian.

Then part b), which is much more sophisticated.