`unliftSwap`🔗

Definition

Unlifts the swap kernel by unlifting the carrier types.

def

unliftSwap (e : Lean.Expr) (eLvl : Lean.Level)
  (proofs : List Lean.Expr) : Lean.MetaM (Lean.Expr × List Lean.Expr)
unliftSwap (e : Lean.Expr)
  (eLvl : Lean.Level)
  (proofs : List Lean.Expr) :
  Lean.MetaM (Lean.Expr × List Lean.Expr)

Code

def unliftSwap (e : Expr) (eLvl : Level) (proofs : List Expr) :
    MetaM (Expr × List Expr) := do
  unless e.isAppOf ``Kernel.swap do
    throwError "Expected the swap kernel, but got {e}."
  let args := e.getAppArgs
  let X' := args[0]!
  let Y' := args[1]!
  let (X, xLvl) ← getOriginalType X'
  let (Y, yLvl) ← getOriginalType Y'
  if X == X' && Y == Y' then
    return (e, proofs)
  else
    let ex ← constructMeasurableEquiv X xLvl eLvl
    let ey ← constructMeasurableEquiv Y yLvl eLvl
    let swap_unlift_proof ← mkAppM ``swap_lift #[ex, ey]
    return (← mkAppOptM ``Kernel.swap #[X, Y, none, none], swap_unlift_proof :: proofs)

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

Audit surface: 2 project declarations, 74 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.

unliftSwap🔗

`unliftSwap`🔗