# [texhax] Puzzling (La)TeX output

Justin C. Walker justin at mac.com
Thu May 4 23:30:06 CEST 2006

Hi,

I tripped over this and can't explain it; I hope someone here will
show me what I am missing:

Using this source:

=====
\newcommand{\dx}{\rm dx}

$\Phi(\dx_i)=dx_i$.
=====

the output has both "dx_i"s the same ("upright", including the
subscript).  If I use

$\Phi({\dx}_i)=dx_i$.

the output is what I would expect (the second "dx", and both "i"s are
"italic").  I'm clearly missing or forgetting something about the way
(La)TeX operates.

Clues?

Thanks for the help.

Regards,

Justin

--
Justin C. Walker, Curmudgeon-At-Large
Institute for the Absorption of Federal Funds
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Some people have a mental horizon of radius zero, and
call it their point of view.
-- David Hilbert
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