{
  "schema_version": "1.0",
  "topic_id": "D09-F06-A08",
  "title": "Ehlers Decycler",
  "purpose": "machine-readable publication-contract verification",
  "data_class": "synthetic teaching input",
  "selected_formula": "Decycler_t=P_t-HighPass_t, with high-pass coefficient determined by cutoff period",
  "canonical_question": "What low-frequency trend remains after subtracting the estimated cycle component?",
  "input_contract": "uniformly sampled finite prices with declared prefilter, coefficients, seed, warm-up, and phase convention",
  "scenario_assertions": [
    {
      "name": "canonical",
      "expected_state": "calculated",
      "assertion": "valid and sufficiently warm synthetic input reaches calculation"
    },
    {
      "name": "boundary",
      "expected_state": "waiting",
      "assertion": "one missing observation or unresolved equality is not coerced to zero"
    },
    {
      "name": "failure",
      "expected_state": "invalid",
      "assertion": "non-finite, misordered, future-dated, or basis-mixed input is withheld"
    }
  ],
  "timing_rule": "An output at t may use only finite, basis-consistent observations available through t; chart alignment never moves the information clock backward.",
  "expected_non_claims": [
    "not historical market data",
    "not a forecast",
    "not a trading instruction",
    "not evidence of profitability"
  ],
  "implementation_status": "Python canonical runtime and audited Node/TypeScript adapter released with topic-owned fixtures and tests"
}