Path: ...!weretis.net!feeder8.news.weretis.net!reader5.news.weretis.net!news.solani.org!.POSTED!not-for-mail
From: Ulrich D i e z <ud.usenetcorrespondence@web.de>
Newsgroups: comp.text.tex
Subject: Re: How to read Web pages with funny backslashes?
Date: Thu, 1 Aug 2024 04:40:30 +0200
Message-ID: <v8esiv$kigt$1@solani.org>
References: <webpage-20240731143147@ram.dialup.fu-berlin.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Injection-Date: Thu, 1 Aug 2024 02:40:31 -0000 (UTC)
Injection-Info: solani.org;
	logging-data="674333"; mail-complaints-to="abuse@news.solani.org"
User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.9.0
Cancel-Lock: sha1:G6t9eblBs3K842Y+V4ziHhRp6HA=
Content-Language: en-US
X-User-ID: eJwFwYEBwDAEBMCVkH90HET2H6F3PK4+AaeDjw9xnRkL1mxUFnGgX961ZcGoPe1dEt0iJj8YNRDx
In-Reply-To: <webpage-20240731143147@ram.dialup.fu-berlin.de>
Bytes: 2524
Lines: 44

Stefan Ram schrieb:

>   I'm totally out of the loop with what the young'uns are up
>   to on the interwebs these days. The other day I stumbled
>   across this webpage that said:
> 
> |Many textbooks, for instance, will tell you that the metric
> |tensor of special relativity takes a form like
> |
> |\[ \eta_{\mu\nu}=\begin{pmatrix}-1&0&0&0\\0&1&0&0\\0&0&1&0 . . .

If this is mathjax and you copy paste to a text file to compile with a
real LaTeX engine, then in the text file holding he LaTeX code you need
to load packages so that all environments and commands are defined.

E.g., https://de.overleaf.com/learn/latex/Matrices says that the
environment pmatrix is defined by the package amsmath, so in the
preamble of your LaTeX code you need to load that package, e.g., via
\usepackage{amsmath}


>   How am I supposed to make heads or tails of this? I figured
>   it was meant to be LaTeX, so I tried to copy it into LaTeX as,
> 
> |\documentclass[a4paper]{article}
> |\begin{document}
> |Here's something that caused me undue confusion over the years . . .
> |Many textbooks, for instance, will tell you that the metric . . .
> |\[ \eta_{\mu\nu}=\begin{pmatrix}-1&0&0&0\\0&1&0&0\\0&0&1&0\\ . . .
> 
>   , but I got hit with:
> 
> |! Misplaced alignment tab character &.
> |l.12 \[ \eta_{\mu\nu}=\begin{pmatrix}-1&
> |                                      0&0&0\\0&1&0&0\\0&0&1&0\\0& . . .
> |
> |?
> 
>   .

Is this the only error message you get?

Sincerely

Ulrich