Proposition 19.8.2.F2503E6C53F2 Let $v\in \mathrm{QPSH}(X)$, let $D,E\geq 0$, and let $F\in C^\infty (X,\mathbb R)$. Suppose that $|u-v|\leq D$ outside the union of the pole sets of $u$ and $v$, and that $\mathrm{d}V'=\mathrm{e}^ F \mathrm{d}V$ with $|F|\leq E$. Then $u$ and $v$ have the same section spaces, and for every positive integer $m$ and every $s$ in the common space $\mathcal H_ m(u)=\mathcal H_ m(v)$,
Proposition 19.8.2F2503E6C53F2
\[ \mathrm{e}^{-mD-E}\| s\| _{m,u}^2 \leq \| s\| _{m,v,\mathrm{d}V'}^2 \leq \mathrm{e}^{mD+E}\| s\| _{m,u}^2. \]
Proof. Off the pole sets, the integrand of $\| s\| _{m,v,\mathrm{d}V'}^2$ is that of $\| s\| _{m,u}^2$ multiplied by $\mathrm{e}^{-m(v-u)+F}$, a function with values between $\mathrm{e}^{-mD-E}$ and $\mathrm{e}^{mD+E}$. Hence one norm is finite if and only if the other is, so the section spaces coincide, and integration gives both estimates. $\square$
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