Hi Jenny,
Thanks again for taking the questions in the spirit they were intended. Just a thought a clean way to make the 9D→4D reduction dynamical (instead of “set higher-dimensional influences to zero”), one simple addition is a constraint term in the action:
ΔS = (k / 2π) ∫{S9} Λ8 ∧ dτ_2
No expectations or assumptions — just offering this as a possible tool that may prove helpful. Thank you again for your work and clarity of presentation.
Best of Luck,
Symbolik