  We show that by working over the absolute base $\mathbb S$ (the categorical
version of the sphere spectrum) instead of $\mathbb S[\pm 1]$ improves our
previous Riemann-Roch formula for $\overline{{\rm Spec\,}\mathbb Z}$. The
formula equates the (integer-valued) Euler characteristic of an Arakelov
divisor with the sum of the degree of the divisor (using logarithms with base
2) and the number $1$, thus confirming the understanding of the ring $\mathbb
Z$ as a ring of polynomials in one variable over the absolute base $\mathbb S$,
namely $\mathbb S[X], 1+1=X+X^2$.
