Spring\(\newcommand\B{\mathrm{B}}
\newcommand\cB{\mathcal{B}}
\newcommand\BC{\mathrm{BC}}
\newcommand\cC{\mathcal{C}}
\newcommand\C{\mathbf{C}}
\newcommand\cF{\mathcal{F}}
\newcommand\cG{\mathcal{G}}
\newcommand\cN{\mathcal{N}}
\newcommand\cP{\mathcal{P}}
\newcommand\Q{\mathbf{Q}}
\newcommand\R{\mathbf{R}}
\newcommand\cS{\mathcal{S}}
\newcommand\T{\mathcal{T}}
\newcommand\cU{\mathcal{U}}
\newcommand\cV{\mathcal{V}}
\newcommand\cW{\mathcal{W}}
\newcommand\cX{\mathcal{X}}
\newcommand\cY{\mathcal{Y}}
\newcommand\Z{\mathbf{Z}}
\DeclareMathOperator\diam{diam}
\DeclareMathOperator\dist{dist}
\DeclareMathOperator\id{id}
\DeclareMathOperator\ord{ord}
\newcommand\blank{\mkern12mu}
\newcommand\isom{\stackrel{\sim}{\longrightarrow}}
\newcommand\norm{\|\blank\|}
\newcommand\simp{\mathrel{\mathop{\kern 0pt\sim}_{\rm p}}}
\newcommand\simq{\mathrel{\mathop{\kern 0pt\sim}_{\rm q}}}
\newcommand{\lt}{<}
\newcommand{\gt}{>}
\newcommand{\amp}{&}
\)