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\begin{document}
\noindent
\textbf{質問1} \\
\hspace{0.3cm}(458page)なぜ$\textbf{H_j}$は実ヒルベルト空間になるのでしょうか?\\
\end{document}
また、ログの表示は
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pLaTeX2e <2017/10/28>+4 (based on LaTeX2e <2017-04-15>)
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LaTeX Warning: Unused global option(s):
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! Missing $ inserted.
<inserted text>
$
l.9 \hspace{0.3cm}(458page)なぜ$\textbf{H_j}
$は実ヒルベルト空間になるのでし...
?
です。よろしくお願いいたします。