Myopia and Anchoring in Dynamic Networks: Determinacy and Persistence
A comment on Angeletos and Huo (2021)
Abstract
Angeletos and Huo (2021) derive equilibrium and an n-mode representation for dynamic networks. Under their printed spectral condition, a signed three-node economy has a one-dimensional family of stationary equilibria and four persistence modes. Absolute small gain restores the 2n/n root count. A nonnegative feed-forward economy satisfies this condition and has a unique equilibrium, while its transfers contain poles of orders three, two, and one. Generalized modes give the replacement representation. Under nearby distinct roots, simple-mode coefficients diverge at rate ε^-2 while canceling to the repeated-pole limit. The observable-representation argument also requires a state-space realization and a separate determinacy premise.
Technical point
The printed spectral condition does not by itself deliver the stated determinacy/root-count conclusion, and repeated roots require generalized rather than simple persistence modes.
Scope
Claims affected
The signed-network determinacy and root-count claim, the simple n-mode representation at repeated roots, and the diagonal modal route used in Proposition 11.
What remains intact
The scalar analysis, inflation application, and calibrated HANK illustration lie outside the affected set; the multivariate result can be repaired with absolute small gain, multiplicity-aware cancellation, generalized modes, and a separate determinacy condition.