opaque Lean.Meta.IndPredBelow.maxBackwardChainingDepth : Lean.Option Nat

structure Lean.Meta.IndPredBelow.Context : Type

• motives : Array (Lake.Name × Lean.Expr)
• typeInfos : Array Lean.InductiveVal
• belowNames : Array Lake.Name
• headers : Array Lean.Expr
• numParams : Nat

The context used in the creation of the below scheme for inductive predicates.

structure Lean.Meta.IndPredBelow.Variables : Type

• target : Array Lean.Expr
• indVal : Array Lean.Expr
• params : Array Lean.Expr
• args : Array Lean.Expr
• motives : Array Lean.Expr
• innerType : Lean.Expr

Collection of variables used to keep track of the positions of binders in the construction of below motives and constructors.

instance Lean.Meta.IndPredBelow.instInhabitedVariables : Inhabited Lean.Meta.IndPredBelow.Variables

structure Lean.Meta.IndPredBelow.BrecOnVariables : Type

• params : Array Lean.FVarId
• motives : Array Lean.FVarId
• indices : Array Lean.FVarId
• witness : Lean.FVarId
• indHyps : Array Lean.FVarId

Collection of variables used to keep track of the local context used in the brecOn proof.

def Lean.Meta.IndPredBelow.mkContext (declName : Lake.Name) : Lean.MetaM Lean.Meta.IndPredBelow.Context

def Lean.Meta.IndPredBelow.mkContext.motiveName (motiveTypes : Array Lean.Expr) (i : Nat) : Lean.MetaM Lake.Name

def Lean.Meta.IndPredBelow.mkContext.mkHeader (motives : Array (Lake.Name × Lean.Expr)) (numParams : Nat) (indVal : Lean.InductiveVal) : Lean.MetaM Lean.Expr

def Lean.Meta.IndPredBelow.mkContext.addMotives (motives : Array (Lake.Name × Lean.Expr)) (numParams : Nat) : Lean.Expr → Lean.MetaM Lean.Expr

def Lean.Meta.IndPredBelow.mkContext.motiveType (indVal : Lean.InductiveVal) : Lean.MetaM Lean.Expr

def Lean.Meta.IndPredBelow.mkContext.mkIndValConst (indVal : Lean.InductiveVal) : Lean.Expr

def Lean.Meta.IndPredBelow.mkCtorType (ctx : Lean.Meta.IndPredBelow.Context) (belowIdx : Nat) (originalCtor : Lean.ConstructorVal) : Lean.MetaM Lean.Expr

def Lean.Meta.IndPredBelow.mkCtorType.addHeaderVars (ctx : Lean.Meta.IndPredBelow.Context) (belowIdx : Nat) (originalCtor : Lean.ConstructorVal) (vars : Lean.Meta.IndPredBelow.Variables) : Lean.MetaM Lean.Expr

def Lean.Meta.IndPredBelow.mkCtorType.addMotives (ctx : Lean.Meta.IndPredBelow.Context) (belowIdx : Nat) (originalCtor : Lean.ConstructorVal) (vars : Lean.Meta.IndPredBelow.Variables) : Lean.MetaM Lean.Expr

partial def Lean.Meta.IndPredBelow.mkCtorType.modifyBinders (ctx : Lean.Meta.IndPredBelow.Context) (belowIdx : Nat) (originalCtor : Lean.ConstructorVal) (vars : Lean.Meta.IndPredBelow.Variables) (i : Nat) : Lean.MetaM Lean.Expr

def Lean.Meta.IndPredBelow.mkCtorType.rebuild (ctx : Lean.Meta.IndPredBelow.Context) (belowIdx : Nat) (originalCtor : Lean.ConstructorVal) (vars : Lean.Meta.IndPredBelow.Variables) : Lean.MetaM Lean.Expr

def Lean.Meta.IndPredBelow.mkCtorType.replaceTempVars (ctx : Lean.Meta.IndPredBelow.Context) (vars : Lean.Meta.IndPredBelow.Variables) (ctor : Lean.Expr) : Lean.Expr

def Lean.Meta.IndPredBelow.mkCtorType.checkCount (ctx : Lean.Meta.IndPredBelow.Context) (domain : Lean.Expr) : Lean.MetaM Bool

def Lean.Meta.IndPredBelow.mkCtorType.mkBelowBinder (ctx : Lean.Meta.IndPredBelow.Context) (vars : Lean.Meta.IndPredBelow.Variables) (binder : Lean.Expr) (domain : Lean.Expr) {α : Type} (k : Nat → Lean.Expr → Lean.MetaM α) : Lean.MetaM α

def Lean.Meta.IndPredBelow.mkCtorType.mkMotiveBinder (ctx : Lean.Meta.IndPredBelow.Context) (vars : Lean.Meta.IndPredBelow.Variables) (indValIdx : Nat) (binder : Lean.Expr) (domain : Lean.Expr) {α : Type} (k : Lean.Expr → Lean.MetaM α) : Lean.MetaM α

def Lean.Meta.IndPredBelow.mkCtorType.copyVarName (oldName : Lean.FVarId) : Lean.MetaM Lake.Name

def Lean.Meta.IndPredBelow.mkConstructor (ctx : Lean.Meta.IndPredBelow.Context) (i : Nat) (ctor : Lake.Name) : Lean.MetaM Lean.Constructor

def Lean.Meta.IndPredBelow.mkInductiveType (ctx : Lean.Meta.IndPredBelow.Context) (i : Fin (Array.size ctx.typeInfos)) (indVal : Lean.InductiveVal) : Lean.MetaM Lean.InductiveType

def Lean.Meta.IndPredBelow.mkBelowDecl (ctx : Lean.Meta.IndPredBelow.Context) : Lean.MetaM Lean.Declaration

partial def Lean.Meta.IndPredBelow.backwardsChaining (m : Lean.MVarId) (depth : Nat) : Lean.MetaM Bool

def Lean.Meta.IndPredBelow.proveBrecOn (ctx : Lean.Meta.IndPredBelow.Context) (indVal : Lean.InductiveVal) (type : Lean.Expr) : Lean.MetaM Lean.Expr

def Lean.Meta.IndPredBelow.proveBrecOn.intros (ctx : Lean.Meta.IndPredBelow.Context) (indVal : Lean.InductiveVal) (m : Lean.MVarId) : Lean.MetaM (Lean.MVarId × Lean.Meta.IndPredBelow.BrecOnVariables)

def Lean.Meta.IndPredBelow.proveBrecOn.applyIH (m : Lean.MVarId) (vars : Lean.Meta.IndPredBelow.BrecOnVariables) : Lean.MetaM (List Lean.MVarId)

def Lean.Meta.IndPredBelow.proveBrecOn.induction (ctx : Lean.Meta.IndPredBelow.Context) (indVal : Lean.InductiveVal) (m : Lean.MVarId) (vars : Lean.Meta.IndPredBelow.BrecOnVariables) : Lean.MetaM (List Lean.MVarId)

def Lean.Meta.IndPredBelow.proveBrecOn.applyCtors (ms : List Lean.MVarId) : Lean.MetaM (List Lean.MVarId)

partial def Lean.Meta.IndPredBelow.proveBrecOn.introNPRec (m : Lean.MVarId) : Lean.MetaM Lean.MVarId

def Lean.Meta.IndPredBelow.proveBrecOn.closeGoal (maxDepth : Nat) (m : Lean.MVarId) : Lean.MetaM Unit

def Lean.Meta.IndPredBelow.mkBrecOnDecl (ctx : Lean.Meta.IndPredBelow.Context) (idx : Nat) : Lean.MetaM Lean.Declaration

def Lean.Meta.IndPredBelow.mkBrecOnDecl.mkType (ctx : Lean.Meta.IndPredBelow.Context) (idx : Nat) : Lean.MetaM Lean.Expr

def Lean.Meta.IndPredBelow.mkBrecOnDecl.mkIH (ctx : Lean.Meta.IndPredBelow.Context) (params : Array Lean.Expr) (motives : Array Lean.Expr) (idx : Fin (Array.size ctx.motives)) (motive : Lake.Name × Lean.Expr) : Lean.MetaM (Lake.Name × (Array Lean.Expr → Lean.MetaM Lean.Expr))

def Lean.Meta.IndPredBelow.getBelowIndices (ctorName : Lake.Name) : Lean.MetaM (Array Nat)

Given a constructor name, find the indices of the corresponding below version thereof.

partial def Lean.Meta.IndPredBelow.getBelowIndices.loop (xs : Array Lean.Expr) (rest : Lean.Expr) (belowIndices : Array Nat) (xIdx : Nat) (yIdx : Nat) : Lean.MetaM (Array Nat)

def Lean.Meta.IndPredBelow.mkBelowMatcher (matcherApp : Lean.Meta.MatcherApp) (belowMotive : Lean.Expr) (below : Lean.Expr) (idx : Nat) : Lean.MetaM (Lean.Expr × Lean.MetaM Unit)

This function adds an additional below discriminant to a matcher application. It is used for modifying the patterns, such that the structural recursion can use the new below predicate instead of the original one and thus be used prove structural recursion.

It takes as parameters:

• matcherApp: a matcher application
• belowMotive: the motive, that the below type should carry
• below: an expression from the local context that is the below version of a predicate and can be used for structural recursion
• idx: the index of the original predicate discriminant.

It returns:

• A matcher application as an expression
• A side-effect for adding the matcher to the environment

def Lean.Meta.IndPredBelow.mkBelowMatcher.addBelowPattern (belowMotive : Lean.Expr) (idx : Nat) (indName : Lake.Name) (lhs : Lean.Meta.Match.AltLHS) : Lean.MetaM Lean.Meta.Match.AltLHS

partial def Lean.Meta.IndPredBelow.mkBelowMatcher.convertToBelow (belowMotive : Lean.Expr) (indName : Lake.Name) (originalPattern : Lean.Meta.Match.Pattern) : Lean.MetaM (Array Lean.LocalDecl × Lean.Meta.Match.Pattern)

this function changes the type of the pattern from the original type to the below version thereof. Most of the cases don't apply. In order to change the type and the pattern to be type correct, we don't simply recursively change all occurrences, but rather, we recursively change occurences of the constructor. As such there are only a few cases:

• the pattern is a constructor from the original type. Here we need to:
  • replace the constructor
  • copy original recursive patterns and convert them to below and reintroduce them in the correct position
  • turn original recursive patterns inaccessible
  • introduce free variables as needed.
• it is an as pattern. Here the contstructor could be hidden inside of it.
• it is a variable. Here you we need to introduce a fresh variable of a different type.

partial def Lean.Meta.IndPredBelow.mkBelowMatcher.transformFields (belowMotive : Lean.Expr) (belowCtor : Lean.Expr) (indName : Lake.Name) (belowFieldOpts : Array (Option Lean.Meta.Match.Pattern)) : Lean.MetaM (Array Lean.LocalDecl × Array Lean.Meta.Match.Pattern)

partial def Lean.Meta.IndPredBelow.mkBelowMatcher.transformFields.loop (belowMotive : Lean.Expr) (indName : Lake.Name) (belowCtor : Lean.Expr) (belowFieldOpts : Array (Option Lean.Meta.Match.Pattern)) (belowFields : Array Lean.Meta.Match.Pattern) (additionalFVars : Array Lean.LocalDecl) : Lean.MetaM (Array Lean.LocalDecl × Array Lean.Meta.Match.Pattern)

def Lean.Meta.IndPredBelow.mkBelowMatcher.toInaccessible : Lean.Meta.Match.Pattern → Lean.MetaM Lean.Meta.Match.Pattern

def Lean.Meta.IndPredBelow.mkBelowMatcher.newMotive (matcherApp : Lean.Meta.MatcherApp) (belowType : Lean.Expr) (ys : Array Lean.Expr) : Lean.MetaM Lean.Expr

def Lean.Meta.IndPredBelow.findBelowIdx (xs : Array Lean.Expr) (motive : Lean.Expr) : Lean.MetaM (Option (Lean.Expr × Nat))

def Lean.Meta.IndPredBelow.mkBelow (declName : Lake.Name) : Lean.MetaM Unit