Proposition 16.28.72.AA248AFFA815 If $v_+(\omega )=+\infty $, the potential $U$ in theorem 13.14.18 can be chosen so that, in addition,
\[ U\in \mathcal E_{\mathrm{env}}(X,\omega ,0),\qquad P_\omega [U]=0. \]
The same conclusions hold for $\varepsilon U$, $0<\varepsilon \leq 1$. Each of these potentials has infinite extended mass and trivial multiplier ideals at every positive weight.
Proof.
Use the smooth nonpositive $\omega $-plurisubharmonic functions $u_ j$, $j\geq 1$, of theorem 13.14.18 and their convergent series $U=\sum _{j\geq 1}2^{-j}u_ j$. For each integer $N\geq 1$, write
\[ U=A_ N+V_ N,\qquad A_ N=\sum _{j\leq N}2^{-j}u_ j,\qquad V_ N=\sum _{j>N}2^{-j}u_ j,\qquad \delta _ N=2^{-N}. \]
The head $A_ N$ is smooth, and since the finite partial sums of the tail decrease, $V_ N\in \mathrm{PSH}(X,\delta _ N\omega )$; the tail is not identically $-\infty $, because $U=A_ N+V_ N$ is not.
Fix $b>1$ and choose $N$ so large that $b\delta _ N\leq 1$. Then
\[ h_ b=bV_ N+\min _ X(bA_ N) \]
is $\omega $-plurisubharmonic, because $\mathrm{dd}^{\mathrm{c}}h_ b\geq -b\delta _ N\omega \geq -\omega $. Moreover, $h_ b\leq bU$. Thus $h_ b\in \mathcal A_ b(U,0)$ for every $b$, and since $U\leq 0$, this proves $U\in \mathcal E_{\mathrm{env}}(X,\omega ,0)$. For $\varepsilon U$, use the tails $\varepsilon V_ N$, and choose $N$ with $b\varepsilon \delta _ N\leq 1$. By proposition 16.28.65, the singularity envelope of each of these potentials is $P_\omega [0]=0$. Their infinite mass and trivial multiplier ideals are given by corollary 13.14.19.
$\square$
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