{
  "handle": "ExchangeRate",
  "mechanism": "A definable ratio between two distinct {{value}} types or {{metric}}s at a specific point in time. It allows agents with orthogonal utility functions to transact.",
  "gloss": "Conversion ratio between value systems",
  "invariants": [
    "Names the source and target {{value}} types and the ratio between them.",
    "Carries the timestamp or window over which the rate is valid.",
    "Invertible where there is no spread: Rate(A→B) equals 1 / Rate(B→A)."
  ],
  "sema_id": "sema:ExchangeRate#mh:SHA-256:ac473b9c9dc4c536a76b952a76d7c7f1cbbf61ef8092404ae98f0f73ea66acfd",
  "sema_ref": "ExchangeRate#ac47",
  "sema_stub": "ac47",
  "_meta": {
    "ring": 1,
    "tier": 1,
    "supersedes": [
      "sema:ExchangeRate#mh:SHA-256:be292881aae1af318995e3c0617ed90f9871d2d7e1c6c64e8083fa9a1b3b94f6",
      "sema:ExchangeRate#mh:SHA-256:eadb7e9b1d80ab8649e81786e787373fd234ae5f949fd84525795ddd5525b729"
    ],
    "path": [
      "Society",
      "Economics"
    ]
  },
  "data_schema": {
    "type": "object",
    "description": "A rate between two value types, valid over a stated window.",
    "properties": {
      "source_type": {
        "type": "string",
        "description": "Value type being converted from."
      },
      "target_type": {
        "type": "string",
        "description": "Value type being converted to."
      },
      "ratio": {
        "type": "number",
        "description": "Units of target per unit of source."
      },
      "valid_from": {
        "type": "string",
        "description": "Start of the validity window."
      },
      "valid_until": {
        "type": "string",
        "description": "End of the validity window, if bounded."
      }
    },
    "required": [
      "source_type",
      "target_type",
      "ratio",
      "valid_from"
    ]
  },
  "failure_modes": [
    "Stale rate: the window has expired and the ratio is applied anyway.",
    "Assumed invertibility: a spread is present and the inverse rate is computed rather than quoted."
  ],
  "dependencies": {
    "references": {
      "metric": "sema:Metric#mh:SHA-256:aa990383741b05e3b798abc7518d9e65c0cc7832b345d4cfed48714ef2501230",
      "value": "sema:Value#mh:SHA-256:37fd75758d04cdd7f57a636ccb5394d463713d60c33b694e37ab71f4a5a896f8"
    }
  },
  "sema_layer": "Society",
  "sema_category": "Economics",
  "used_by": {
    "yields": {
      "ValuePeg": "sema:ValuePeg#mh:SHA-256:e4409fa4a0947af3497c4c4e059fe147be6a92415c18751aa12baa5983b3fea6"
    }
  }
}