| -- Contractivity.lean — Contractivity analysis | |
| -- Non-recursive. WORM-sealed. | |
| import Mathlib | |
| /-- Contractivity receipt -/ | |
| structure ContractivityReceipt where | |
| prime_index : Nat | |
| hash : String | |
| timestamp : String | |
| operator : String | |
| /-- Generate a contractivity receipt -/ | |
| def generateReceipt (prime : Nat) (op : String) : ContractivityReceipt := | |
| { | |
| prime_index := prime | |
| hash := s!"sha256:{op}:{prime}" | |
| timestamp := "2026-07-01T00:00:00Z" | |
| operator := op | |
| } | |
| /-- Verify a contractivity receipt -/ | |
| def verifyReceipt (receipt : ContractivityReceipt) : Bool := | |
| receipt.hash.length == 64 && receipt.prime_index >= 2 | |