`liftSwap`🔗

Definition

Lifts a swap kernel by lifting the carrier types.

def

liftSwap (e : Lean.Expr) (maxLvl : Lean.Level)
  (proofs : List Lean.Expr) : Lean.MetaM (Lean.Expr × List Lean.Expr)
liftSwap (e : Lean.Expr)
  (maxLvl : Lean.Level)
  (proofs : List Lean.Expr) :
  Lean.MetaM (Lean.Expr × List Lean.Expr)

Code

def liftSwap (e : Expr) (maxLvl : 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 xLvl := (← getDecLevel X)
  let yLvl := (← getDecLevel Y)
  let ex ← constructMeasurableEquiv X xLvl maxLvl
  let ey ← constructMeasurableEquiv Y yLvl maxLvl
  let (X', _) ← getTypesFromMeasurableEquiv ex
  let (Y', _) ← getTypesFromMeasurableEquiv ey
  let swap_lift_proof ← mkAppM ``swap_lift #[ex, ey]
  return (← mkAppOptM ``Kernel.swap #[X', Y', none, none], swap_lift_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, 110 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.

liftSwap🔗

`liftSwap`🔗