Copied from 
http://planetmath.org/encyclopedia/ExamplesOfNonMatrixLieGroup.html

While most well-known Lie groups are matrix groups, there do in fact exist Lie groups which are not matrix groups. That is, they have no faithful finite dimensional representations.

For example, let $H$ be the real Heisenberg group

$$H=\{\begin{pmatrix} 1 &amp; a &amp; b\newline 0&amp;1&amp;c\newline 0 &amp;0 &amp;1\end{pmatrix}\mid a,b,c\in\mathbb{R} \},$$

and $\Gamma$ the discrete subgroup

$$\Gamma=\{\begin{pmatrix} 1 &amp; 0 &amp; n\newline0&amp;1&amp;0\newline 0 &amp;0 &amp;1\end{pmatrix}\mid n\in\mathbb{Z}\}.$$

The subgroup $\Gamma$ is central, and thus normal. The Lie group $H/\Gamma$ has no faithful finite dimensional representations over $\mathbb{R}$ or $\mathbb{C}$.

Non-linear Lie group
I'm a web designer currently working with a very demanding client.

I presented them with designs back in May and I'm still working through amends with them. They are making changes to everything and although I know amends are to be expected, it's really getting to be frustrating. I'm currently working every evening on the list of new amends they have. Tiny things like "make this blue" or "change the width of this" or "make this gap smaller".

I know amends need to be made and that's fine, but how do you handle when there are just too many? I've counted the comments on inVision and there have been 185 amends on 6 pages of a website design. 

Some of them change, and then change again, and then change again and again. For example they wanted to add a strapline, so I added it, adjusted all the menus to accomodate is across the 6 pages. Then they wanted to change the text, so I changed it and updated it across all 6 documents. Now that it's changed, they want to make the menu smaller so now I have to go back and change the menu again.

I quoted based on time I thought it would take to complete the designs with some time for amends but I've more than tripled the time. I haven't explained to them early enough in the process that amends beyond the normal would cost them more so I'm going to have to swallow the cost this time, but should I lay this out better with future clients?

How do you handle amends? Do you put an estimated time on them at the beginning, and then charge more if they go over this? Or do you do something different?
