{"artifact_id":"L1-431","layer":"L1","title":"System Identification (N4SID/ARX)","domain":"Control Theory","sub_domain":"System identification","physics_fingerprint":{"L_DAG":3.0,"title":"System Identification (N4SID/ARX)","domain":"Control Theory","carrier":"N/A","primitives":["S.n4sid.subspace_id","N.pointwise","O.chi2.one_step_ahead"],"sub_domain":"System identification","noise_model":"gaussian","problem_class":"parameter_estimation","solution_space":"system_matrices_ABCD","difficulty_delta":3,"integration_axis":"time_series","sensing_mechanism":"input_output_system_identification"},"observable_profile":{"metric":"model_fit_percent","regime":"Existence of the recovered system_matrices_ABCD is guaranteed within the declared Omega bounds. Uniqueness holds on the measurement-supported subspace; out-of-support modes are controlled by declared priors. Stability is conditionally stable (kappa_eff ~= 100); undermodeling_order_mismatch dominates the stability cliff; the remaining mismatch parameters contribute higher-order bias terms. Gaussian sets the irreducible data-fidelity floor.","secondary":"VRMS_validation"},"size_tiers":{"center_spec":{"omega":{"input_SNR_dB":30,"N_data_points":1000,"model_order_n":4,"bandwidth_fraction":0.3},"input_format":"measurement_only","problem_class":"parameter_estimation","forward_operator":"input_output_system_identification","epsilon_fn_center":"85 model_fit_percent"},"omega_bounds":{"input_SNR_dB":[10,60],"N_data_points":[100,100000],"model_order_n":[1,20],"bandwidth_fraction":[0.1,0.9]},"epsilon_bounds":{"model_fit_percent":[50,99]},"allowed_problem_classes":["parameter_estimation"],"allowed_omega_dimensions":["model_order_n","N_data_points","input_SNR_dB","bandwidth_fraction"],"allowed_forward_operators":["input_output_system_identification"]},"hardness_fn":{"type":"epsilon_fn","delta":3,"kappa":2000,"metric":"model_fit_percent"},"initiator_dataset":[{"name":"primary","weight":1.0,"ipfs_cid":null,"license_hash":null}],"status":"testnet","staked_pwm":0.0,"chain_hash":"0xb4f52cafc9f4e894c5b66fa7ceff50fa60401595be22250bc135c329cfc60b6a","chain_tx_hash":"0x49e90e1df5a572b0082bb7997fd503f8ae9f9b718508029fbad92aa6c1e38f61","chain_block":41555240}