餵食
\documentclass{article}
\pagestyle{empty}
%\usepackage[slantedGreek,subscriptcorrection]{newtx}% this is what I use with many of other packages in a non-minimal example.
%% Text skips with glue being half of the value of the argument (cf. http://tex.stackexchange.com/q/657443, http://tex.stackexchange.com/a/657448, and http://tex.stackexchange.com/a/672701):
\newcommand{\flexibleHSkip}[1]{%
\hskip#1
plus.5\dimexpr\ifdim #1<0pt -\fi#1\relax
minus.5\dimexpr\ifdim #1<0pt -\fi#1\relax
\relax
}
\begin{document}\noindent
Consider the set \(Y\). Let \ldots\\
Consider the set \(Y\)\flexibleHSkip{-.1em}. \flexibleHSkip{.1em}Let \ldots\\
Consider the set \(Y\)\flexibleHSkip{-.1em}.\flexibleHSkip{.1em} Let \ldots\\
Consider the set \(Y\), and let \ldots\\
Consider the set \(Y\)\flexibleHSkip{-.1em}, \flexibleHSkip{.1em}and let \ldots\\
Consider the set \(Y\)\flexibleHSkip{-.1em},\flexibleHSkip{.1em} and let \ldots
\end{document}
到pdflatex產量
使用標準字體（Computer Modern）和
與NewTX。間距縮小的版本
答案1
我只需將其放入.數學中，無論如何，它都會從 mathrm 字體中獲取，並允許字體指定的字距生效。
\documentclass{article}
\begin{document}
$Y$. ABC
$Y.$ ABC
\end{document}