有没有办法覆盖 LaTeX 关于双下标和上标的错误？
关于 LaTeX 的一个让我困扰的小问题。当一个人在写作
a^b^c, a_b_c
或
a'^b
数学模式下时，LaTeX 会给出一条错误消息，抱怨有多个上标/下标。在替换包含上标/下标的字符串或使用撇号 ' 时，这尤其令人烦恼。
有没有办法覆盖错误并让 LaTeX 简单地输出
a^{bc} a_{bc} {a'}^b
等等？
Minor point about LaTeX that bothers me. When one writes
a^b^c, a_b_c
or
a'^b
in math mode, LaTeX gives an error message complaining about multiple super/subscripts. This is particularly annoying after replacing a string containing a super/subscript or when using the apostrophe, '.
Is there a way to override the error and have LaTeX simply output
a^{bc} a_{bc} {a'}^b
and so on?
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以下是你所希望的
The following is what you wish
这是您真正应该被警告的情况之一，并且必须按照您想要的方式放置大括号 - 或者编写没有双下标/上标的内容，如果这就是您的意思。一般来说，当您使用上标表示求幂而不是索引时，
a^b^c = a^{b^c}，因此您描述的输出在某些情况下肯定是不正确的。当然，如果它们是上标索引，您可能指的是a^{bc}，但是 LaTeX 如何知道呢？对于下标，如果您确实指的是a_{n_k}，而不是a_{nk}，该怎么办？ （即双索引与索引序列）（当然，如果这作为替换的一部分出现，您可能可以找到一种方法来修复它作为替换的一部分。）
This is one of those cases where you really should be warned, and have to place the braces the way you want them - or write something without a double sub/superscript, if that's what you mean. Generally, when you're using superscript to indicate exponentiation, not indexing,
a^b^c = a^{b^c}, so the output you describe is definitely incorrect in some cases. Sure, if they're superscript indices, you might meana^{bc}, but how's LaTeX to know? And for subscripts, what if you really do meana_{n_k}, nota_{nk}? (that is, double-indexing vs. a sequence of indices)(And of course, if this crops up as part of a substitution, you can probably figure out a way to fix it as part of the substitution.)
虽然Alexeys的答案应该是被接受的——它完全符合作者想要的——让我注意到还有Latex可用的软件包正是这样做的，最值得注意的是 Tensor 软件包 可以做到这一点：
您为第一个示例编写
\Gamma\indices{^\mu_{\nu\rho}}。相反，使用 Alexeys 答案，您只需编写\Gamma^\mu_{\nu\rho} 显然更短。但是，catcode 对^和_字符的重新定义将破坏这些字符在常规文本中的出现，这很烦人，尤其是在数学模式之外。While Alexeys answer should be the acceppted one -- it does exactly what the author wants -- let me note there are also Latex packages available doing exactly this, most notably the Tensor package can do this:
You write
\Gamma\indices{^\mu_{\nu\rho}}for the first example. In contrast, with Alexeys answer you just can write\Gamma^\mu_{\nu\rho}which is obviously shorter. However, the catcode redefinition of the^and_characters will break any occurence of these characters in regular text which is annoying especially outside of math mode.