`idME`🔗

Opaque

Compute a measurable equivalence between a type and itself by recursively decomposing products.

opaque

idME (X : Lean.Expr) : Lean.MetaM Lean.Expr
idME (X : Lean.Expr) :
  Lean.MetaM Lean.Expr

Code

partial def idME (X : Expr) : MetaM Expr

Proof

do
  match X.getAppFn with
  | Expr.const ``Prod _ =>
    let args := X.getAppArgs
    let id1 ← idME args[0]!
    let id2 ← idME args[1]!
    mkAppM ``MeasurableEquiv.prodCongr #[id1, id2]
  | Expr.const ``PUnit [xLvl] | Expr.const ``Unit [xLvl] =>
    let xLvl ← match xLvl with
      | Level.succ l => pure l
      | _ => throwError "Expected a successor level for PUnit/Unit, got: {xLvl}."
    let punitME := mkConst ``MeasurableEquiv.punit [xLvl, xLvl]
    mkAppM' punitME #[]
  | _ =>
    mkAppOptM ``MeasurableEquiv.refl #[X, none]

Actions: Source · Open Issue

Meaning last changed in v4.34.0-rc2-1-g439785b (2026-08-23).

Self-contained, with its dependencies inlined and proofs replaced by sorry: download the raw file · open it in the Lean web editor.

Dependency graph

Nothing to draw. Its statement rests on no other declaration in this project, and names nothing from a package left unaudited — so the graph is this declaration alone. That is the answer, not a missing picture.

Audit surface: 0 project declarations, 2 external constants

✓ Proved: no sorry anywhere in its closure

This is the tool's own reading of one build's recorded axioms, and it is not robust against an author who wants it to pass. Checking meant to be relied on should go through Comparator, which replays the proof through the kernel from an export against an explicit list of permitted axioms.

idME🔗

`idME`🔗