Thank you for your fast reply! (Or is there a +1 button, like in SO?)

On Thursday, November 2, 2017 at 11:23:07 PM UTC+1, John MacFarlane wrote:

+++ Dániel Tüzes [Nov 02 17 14:31 ]:
>   When I try to transform my latex file to html, it says:
>
>     pandoc analizis.tex -o analizis1b_reversed.html
>     [WARNING] Could not load include file 'lmodern.sty' at line 3 column
>     21
>     [WARNING] Could not load include file 'amssymb.sty' at line 4 column
>     29
>     [WARNING] Could not load include file 'amsmath.sty' at line 4 column
>     29
>

These are nothing to worry about.  They just say that pandoc
isn't reading and parsing the .sty files.  (It won't do that
unless they're in the working directory or --resource-path.)
But usually that's just fine.  Pandoc knows about lots of
macros defined in common styles.

This is the second concerned message we've gotten due to
these warnings.  This tempts me to demote these to INFO
messages, but the problem is that, if you're doing
a \usepackage with your own custom .sty file that lives
in the working directory, you'd really like to me notified
if pandoc can't load it.  Still, on balance, maybe we should
make these INFO messages.  Any thoughts on that?


>   end so on... Then of course come these errors:
>
>   [WARNING] Could not convert TeX math '{\mathbf{v},\mathbf{u}} =
>   {\sum\limits_{j= 1}^{n}{v_{j}u_{j}}}', rendering as TeX
>   [WARNING] Could not convert TeX math '\left\| a \parallel \right.: =
>   \sqrt{a,a}', rendering as TeX

By default pandoc will try to "fake" the math with unicode,
but it can't do that for complex things like this.  If you
want to use math, you should explore the various options in
the manual for using math with HTML (e.g. mathjax).  If you
use those options, the warnings will go away.