{
  "system_id": "double_pendulum",
  "name": "Double pendulum",
  "category": "chaotic",
  "equations": "Coupled second-order nonlinear equations for two angles θ1, θ2 of a planar double pendulum under gravity.",
  "parameters": {
    "m1": 1.0,
    "m2": 1.0,
    "l1": 1.0,
    "l2": 1.0,
    "g": 9.81
  },
  "description_simple": "A physical system with two connected pendulum arms that, for many initial conditions, exhibits chaotic motion.",
  "description_complex": "A deterministic mechanical system consisting of two rigid rods connected in series and free to swing in a plane under gravity. The governing equations are highly nonlinear, and for generic initial conditions the motion shows deterministic chaos: strong sensitivity to initial conditions, complex trajectories in phase space, and no simple periodic or quasi-periodic attractor.",
  "truth_assignment": {
    "Chaotic": true,
    "Deterministic": true,
    "PosLyap": true,
    "Sensitive": true,
    "StrangeAttr": true,
    "PointUnpredictable": true,
    "StatPredictable": true,
    "QuasiPeriodic": false,
    "Random": false,
    "FixedPointAttr": false,
    "Periodic": false
  }
}