Text Formatting ⇒ Compile error

[ytrewq]

Hey,
I'm new to LaTeX. I have to write text which should look the same as text on paper that teacher gave us, but I have compile error.
https://www.writelatex.com/read/yjfqmbtsgczm
It says 'missing { inserted" but IMO everything is OK. I really don't know what to do so would be nice if I got help here.
Sorry for poor English and thanks for your time.

[Johannes_B]

Please post your code in form of a minimal example. This makes it much easier to help and you might have the satisfaction of finding errors on your own.

Code: Select all

\documentclass[a4paper]{article}
\usepackage{amsmath}
\begin{document}
The two algebras are isomorphic, the isomorphism being given by

\begin{align}
\ell_{\alpha}(J^{\pm}_{m})&= K^{\pm}_{m\pm\alpha} \\%(A.21)
\ell_{\alpha}(J^{3}_{m})&= K^{3}_{m} + ^{\alpha}_{2}k\delta_{m,0} \\%(A.22)
\ell_{\alpha}(L_{m})&= (L^{\hat{}} + \alpha K^{3}_{m} +
^{k}_{4}\alpha^{2}\delta_{m,0}) \tag{A.23}%You can tag if you really need it
\end{align}
\end{document}

You said that you are new to latex, that is absolutely no problem. But please read some introductory material, to get the grips. There are mechanisms for the things that you are doing by hand. You can save a lot of time in the future if you invest some by reading right now.

PLease also read: Math mode

Best regards
Johannes

Please note, that i haven't read everything, since it is not my homework.

[ytrewq]

Thanks for help and for fixed first part! I fixed next errors the same way u did first and it's compiled. I'm still not sure what are these added marks doing, but that doesn't matter right now. Now I must fix some things up and send it to my teacher, I can learn what is exactly going on later .
Again big thanks!