چکیده مقاله
This paper develops a dynamic stochastic general equilibrium DSGE framework in which the macroeconomy is modeled as a Riemannian manifold with endogenously time varying curvature Unlike standard linearized DSGE models, the proposed framework captures nonlinear shock amplification through a metric tensor derived from welfare based adjustment costs, providing rigorous microfoundations for the geometric structure We term this the Najkar framework to distinguish it from conventional linearized approaches Scalar curvature κserves as an operational measure of amplification potential: higher curvature indicates greater sensitivity of the economy to structural shocks, analogous to how a curved surface distorts distances relative to flat space The model is estimated via Bayesian methods on quarterly Iranian data spanning 1991Q1–2021Q4 — an economy defined by dual exchange rate regimes, recurring sanctions episodes, a large informal sector 30–40% of GDP , and volatile oil revenues Estimation reveals that κrises from 0 04–0 06 during normal periods to 0 15–0 18 during sanctions crises, a three to fourfold increase High curvature states κ>0 10 characterize approximately 23% of the sample Relative to standard first order linearized DSGE models, this framework improves four quarter ahead forecasts by 18–23% during these high curvature episodes Counterfactual policy experiments yield two main findings First, a curvature contingent monetary policy rule — augmenting the standard Taylor rule with a term ϕ_κ κ_t, where the optimal response coefficient is ϕ_κ≈ 0 2— delivers welfare gains equivalent to 2 6% of steady state consumption, with the rule prescribing systematically tighter policy as curvature rises Second, structural reforms that reduce nominal rigidities lower equilibrium curvature by 35%, generating additional welfare benefits worth 3 2% of consumption Together, these results demonstrate that the Najkar framework provides actionable guidance for macroeconomic management in emerging markets exposed to sanctions, financial fragmentation, and deep structural nonlinearities
کلیدواژهها
نویسندگان
Nastaran Najkar
Department of Agricultural Economics, International Campus of Ferdowsi University of Mashhad, Iran
شیوه ارجاع
Najkar, Nastaran,1404,Economic Geometry and Crisis Dynamics: A Riemannian DSGE Framework for Iran’s Economy,22th International Conference on New Research in Management, Economics, Accounting and Banking (ICMEAB)
ارائهشده در
مجموعه مقالات بیست دومین کنفرانس بین المللی پژوهش های نوین در مدیریت، اقتصاد، حسابداری و بانکداری26 اسفند 1404