Proposition: Q3 is open at its first item

Identified: the construction (eq:Dfrom) of $\mathsf{D}$ from ${\dot{a}}_2$; the role of $g$ as the switch; the order bound $|\alpha |+|\beta |\le 2$. Open, each reduced to one sheet and one sentence: $\mathsf{A}$ (XIV-H input:EC quoting (eq:afrak)); ${\sigma }_{\epsilon }$, $f$ (XIV-H preceding eq:L; XII-B's cutoff only through a quotation inside XIV-H; XII-D's $f$ only through a quotation); $a_2$, hence the value of $\mathsf{D}$ (XIV-H input:EC quoting (eq:a2)); ${q^{L,I,J}}_{\alpha \beta }$ (expansion of XII-C's cubic, not performed); $\mathsf{P}$, $\mathfrak{b}$ (XIV-H source incidence); ${E^{\mathrm{A}}}_m$ (declaration as advanced inverse). Q3 does not pass.

Proof. The subsections above.