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So, I've been trying to renewcommand \alpha by assigning it parameters in Latex. This is what I have for my preamble and the body...(seen below). On line 12, I attempted to create such a "function", but I continue to get the following errors

for line 14: ! TeX capacity exceeded, sorry [input stack size=5000].\alpha #1->\alpha (#1) ...\mathcal{C}^{\infty})\) is a map \(\alpha:

and for line 1: ! ==> Fatal error occurred, no output PDF file produced! Can someone please help!?

\usepackage[utf8]{inputenc}
\usepackage{latexsym, braket, amsmath, amsfonts, amssymb,amsthm, mathtools, standalone, setspace, graphicx, tikz, pgfplots, nccmath}
\pgfplotsset{compat=newest}
\usepackage[english]{babel}
\newcommand{\Def}{\underline{\textbf{Definition:}}}
\renewcommand{\labelenumiii}{\roman{enumiii}}
\renewenvironment{proof}{\textbf{Proof:}\setlength{\parindent}{5em}
\setlength{\parskip}{1em} \renewcommand{\qedsymbol}{$\blacksquare$}}{\hfill \qedsymbol}
\DeclarePairedDelimiter\abs{\lvert}{\rvert}
\renewcommand{\sup}[1]{\mathrm{sup}(#1)}
\renewcommand{\inf}[1]{\mathrm{inf}(#1)}
\renewcommand{\alpha}[1]{\alpha(#1)}
\newcommand{\eps}{\epsilon}
\usepackage{anysize}\marginsize{.5in}{.5in}{.5in}{.5in}
\setlength{\parindent}{3em}
\setlength{\parskip}{1em}
\author{Dwight Dinkins}
\title{DIfferential Geometry ITCP: Lecture 1}
\date{March 19, 2020}
\setstretch{2}%
\begin{document}
\maketitle
\Def A differentiable curve \((\mathcal{C}^{\infty})\) is a map \(\alpha: I \longrightarrow \mathbb{R}^{3}\), \(I=(a,b)\subset\mathbb{R}\), such that \[\alpha{t}=( x(t), y(t),z(t))\), \(x,y,z\) are \(\mathcal{C}^{\infty}\) functions.
\end{document}```


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  • 1
    You can't do it like that, you need first to copy the current definition like \let\oldalpha=\alpha and then \renewcommand{\alpha}[1]{\oldalpha(#1)}. – campa Mar 19 '20 at 16:12
  • You can redefine \alpha as in the comments of @campa, but I don't believe this is what you want. First you call \alpha a differentiable curve and you don't want any kind of bracket here, then you want \alpha(...)and call both by the same name. You can do it any way with a optional parameter but I believe it is better to call the second one by other name, say \newcommand{\al}[1]{\alpha(#1)} or anything else. Same comments on \infand \sup. – Luis Turcio Mar 19 '20 at 16:21
  • 1
    That is not a good idea, give your macro a different name. Also your proof env redefinition isn't good as the end marker placement can easily fail in this naïve redefinition (a lot of people have tried to do it like this and learnt why it is not recommended) – daleif Mar 19 '20 at 16:22
  • @daleif Could you elaborate on my redefinition of my proof environment? Thanks you all for the help? – user8317867 Mar 19 '20 at 16:53
  • If the text is just right then the qed marker goes to the next line, but at the left edge, the \hfill is ignored, that looks inconsistent and is annoying having to check by hand. – daleif Mar 19 '20 at 16:55