LaTeX.org

Once and again I get this annoying problem.
I have a document, no errors, no strange warnings, everything is nice and smooth.
Then I add maybe a line or two with plain text. After compiling
these new lines does not show up in the output. By now nothing I do
will change the output; for example if I ...

hi
i think you are wrong,
http://www.ctex.org/documents/packages/math/ntheorem.pdf page 11:
amsthm.sty conflicts with the definition of theorem layouts in theorem.sty, some
features of amsthm.sty have been incorporated into option [amsthm] which has to
be used instead of \usepackage{amsthm}. (i ...

Apparently the amsmath, amsthm packages together with the ntheorem package can cause troubles according to several sources, i think im experiencing this.
is it even possible to have use \begin{split} when ntheorem is used?

even a silly example like
\[
\begin{split}
a & = b \\
& = c \\
& = d ...

thank you balf.

hi everyone
how to get a end symbol in a theorem (for example) environment, similar to the q.e.d symbol at the end of a proof environment?