Process when an new equation is added to a congruence closure #
The monad for the cc
tactic stores the current state of the tactic.
Instances For
Run a computation in the CCM
monad.
Equations
- x.run c = StateRefT'.run x c
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Update the todo
field of the state.
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Update the acTodo
field of the state.
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Update the cache
field of the state.
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Read the todo
field of the state.
Equations
- Mathlib.Tactic.CC.CCM.getTodo = do let __do_lift ← get pure __do_lift.todo
Instances For
Read the acTodo
field of the state.
Equations
- Mathlib.Tactic.CC.CCM.getACTodo = do let __do_lift ← get pure __do_lift.acTodo
Instances For
Read the cache
field of the state.
Equations
- Mathlib.Tactic.CC.CCM.getCache = do let __do_lift ← get pure __do_lift.cache
Instances For
Look up an entry associated with the given expression.
Equations
- Mathlib.Tactic.CC.CCM.getEntry e = do let __do_lift ← get pure (Batteries.RBMap.find? __do_lift.entries e)
Instances For
Use the normalizer to normalize e
.
If no normalizer was configured, returns e
itself.
Equations
- Mathlib.Tactic.CC.CCM.normalize e = do let __do_lift ← get match __do_lift.normalizer with | some normalizer => liftM (normalizer.normalize e) | x => pure e
Instances For
Add a new entry to the end of the todo list.
See also pushEq
, pushHEq
and pushReflEq
.
Equations
- Mathlib.Tactic.CC.CCM.pushTodo lhs rhs H heqProof = Mathlib.Tactic.CC.CCM.modifyTodo fun (todo : Array Mathlib.Tactic.CC.TodoEntry) => todo.push (lhs, rhs, H, heqProof)
Instances For
Add the equality proof H : lhs = rhs
to the end of the todo list.
Equations
- Mathlib.Tactic.CC.CCM.pushEq lhs rhs H = Mathlib.Tactic.CC.CCM.pushTodo lhs rhs H false
Instances For
Add the heterogeneous equality proof H : HEq lhs rhs
to the end of the todo list.
Equations
- Mathlib.Tactic.CC.CCM.pushHEq lhs rhs H = Mathlib.Tactic.CC.CCM.pushTodo lhs rhs H true
Instances For
Add rfl : lhs = rhs
to the todo list.
Equations
Instances For
Return the root expression of the expression's congruence class.
Equations
- Mathlib.Tactic.CC.CCM.getRoot e = do let __do_lift ← get pure (__do_lift.root e)
Instances For
Is e
the root of its congruence class?
Equations
- Mathlib.Tactic.CC.CCM.isCgRoot e = do let __do_lift ← get pure (__do_lift.isCgRoot e)
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Update the child
so its parent becomes parent
.
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Return true iff the given function application are congruent
e₁
should have the form f a
and e₂
the form g b
.
See paper: Congruence Closure for Intensional Type Theory.
Return the CongruencesKey
associated with an expression of the form f a
.
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Return the SymmCongruencesKey
associated with the equality lhs = rhs
.
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Try to find a congruence theorem for an application of fn
with nargs
arguments, with support
for HEq
.
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Try to find a congruence theorem for the expression e
with support for HEq
.
Equations
- Mathlib.Tactic.CC.CCM.mkCCCongrTheorem e = let fn := e.getAppFn; let nargs := e.getAppNumArgs; Mathlib.Tactic.CC.CCM.mkCCHCongrTheorem fn nargs
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Record the instance e
and add it to the set of known defeq instances.
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Treat the entry associated with e
as a first-order function.
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- One or more equations did not get rendered due to their size.
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Update the modification time of the congruence class of e
.
Does the congruence class with root root
have any HEq
proofs?
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- One or more equations did not get rendered due to their size.
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Apply symmetry to H
, which is an Eq
or a HEq
.
- If
heqProofs
is true, ensure the result is aHEq
(otherwise it is assumed to beEq
). - If
flipped
is true, applysymm
, otherwise keep the same direction.
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- One or more equations did not get rendered due to their size.
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In a delayed way, apply symmetry to H
, which is an Eq
or a HEq
.
- If
heqProofs
is true, ensure the result is aHEq
(otherwise it is assumed to beEq
). - If
flipped
is true, applysymm
, otherwise keep the same direction.
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- One or more equations did not get rendered due to their size.
Instances For
Apply symmetry to H
, which is an Eq
or a HEq
.
- If
heqProofs
is true, ensure the result is aHEq
(otherwise it is assumed to beEq
). - If
flipped
is true, applysymm
, otherwise keep the same direction.
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- One or more equations did not get rendered due to their size.
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Are e₁
and e₂
known to be in the same equivalence class?
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Is e₁ ≠ e₂
known to be true?
Note that this is stronger than not (isEqv e₁ e₂)
:
only if we can prove they are distinct this returns true
.
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Instances For
Is the proposition e
known to be true?
Equations
Instances For
Is the proposition e
known to be false?
Equations
- Mathlib.Tactic.CC.CCM.isEqFalse e = Mathlib.Tactic.CC.CCM.isEqv e (Lean.Expr.const `False [])
Instances For
Apply transitivity to H₁
and H₂
, which are both Eq
or HEq
depending on heqProofs
.
Equations
- Mathlib.Tactic.CC.CCM.mkTrans H₁ H₂ heqProofs = if heqProofs = true then Lean.Meta.mkHEqTrans H₁ H₂ else Lean.Meta.mkEqTrans H₁ H₂
Instances For
Apply transitivity to H₁?
and H₂
, which are both Eq
or HEq
depending on heqProofs
.
If H₁?
is none
, return H₂
instead.
Equations
- Mathlib.Tactic.CC.CCM.mkTransOpt H₁? H₂ heqProofs = match H₁? with | some H₁ => Mathlib.Tactic.CC.CCM.mkTrans H₁ H₂ heqProofs | none => pure H₂
Instances For
Use congruence on arguments to prove lhs = rhs
.
That is, tries to prove that lhsFn lhsArgs[0] ... lhsArgs[n-1] = lhsFn rhsArgs[0] ... rhsArgs[n-1]
by showing that lhsArgs[i] = rhsArgs[i]
for all i
.
Fails if the head function of lhs
is not that of rhs
.
If e₁ : R lhs₁ rhs₁
, e₂ : R lhs₂ rhs₂
and lhs₁ = rhs₂
, where R
is a symmetric relation,
prove R lhs₁ rhs₁
is equivalent to R lhs₂ rhs₂
.
- if
lhs₁
is known to equallhs₂
, returnnone
- if
lhs₁
is not known to equalrhs₂
, fail.
Use congruence on arguments to prove e₁ = e₂
.
Special case: if e₁
and e₂
have the form R lhs₁ rhs₁
and R lhs₂ rhs₂
such that
R
is symmetric and lhs₁ = rhs₂
, then use those facts instead.
Turn a delayed proof into an actual proof term.
Use the format of H
to try and construct a proof or lhs = rhs
:
If asHEq
is true
, then build a proof for HEq e₁ e₂
.
Otherwise, build a proof for e₁ = e₂
.
The result is none
if e₁
and e₂
are not in the same equivalence class.
Build a proof for e₁ = e₂
.
The result is none
if e₁
and e₂
are not in the same equivalence class.
Build a proof for HEq e₁ e₂
.
The result is none
if e₁
and e₂
are not in the same equivalence class.
Build a proof for e = True
. Fails if e
is not known to be true.
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Build a proof for e = False
. Fails if e
is not known to be false.
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- One or more equations did not get rendered due to their size.
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Build a proof for a = b
. Fails if a
and b
are not known to be equal.
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Auxiliary function for comparing lhs₁ ~ rhs₁
and lhs₂ ~ rhs₂
,
when ~
is symmetric/commutative.
It returns true
(equal) for a ~ b
b ~ a
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Given k₁ := (R₁ lhs₁ rhs₁, `R₁)
and k₂ := (R₂ lhs₂ rhs₂, `R₂)
, return true
if
R₁ lhs₁ rhs₁
is equivalent to R₂ lhs₂ rhs₂
modulo the symmetry of R₁
and R₂
.
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Given e := R lhs rhs
, if R
is a reflexive relation and lhs
is equivalent to rhs
, add
equality e = True
.
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If the congruence table (congruences
field) has congruent expression to e
, add the
equality to the todo list. If not, add e
to the congruence table.
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If the symm congruence table (symmCongruences
field) has congruent expression to e
, add the
equality to the todo list. If not, add e
to the symm congruence table.
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Given subsingleton elements a
and b
which are not necessarily of the same type, if the
types of a
and b
are equivalent, add the (heterogeneous) equality proof between a
and b
to
the todo list.
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Given the equivalent expressions oldRoot
and newRoot
the root of oldRoot
is
newRoot
, if oldRoot
has root representative of subsingletons, try to push the equality proof
between their root representatives to the todo list, or update the root representative to
newRoot
.
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Get all lambda expressions in the equivalence class of e
and append to r
.
e
must be the root of its equivalence class.
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Remove fn
and expressions whose type isn't def-eq to fn
's type out from lambdas
,
return the remaining lambdas applied to the reversed arguments.
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Given a
, a₁
and a₁NeB : a₁ ≠ b
, return a proof of a ≠ b
if a
and a₁
are in the
same equivalence class.
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Given aNeB₁ : a ≠ b₁
, b₁
and b
, return a proof of a ≠ b
if b
and b₁
are in the
same equivalence class.
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If e
is of the form op e₁ e₂
where op
is an associative and commutative binary operator,
return the canonical form of op
.
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Given lhs
, rhs
, and header := "my header:"
, Trace my header: lhs = rhs
.
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Trace the state of AC module.
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Return the proof of e₁ = e₂
using ac_rfl
tactic.
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Given tr := t*r
sr := s*r
tEqs : t = s
, return a proof for tr = sr
We use a*b
to denote an AC application. That is, (a*b)*(c*a)
is the term a*a*b*c
.
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Given ra := a*r
sb := b*s
ts := t*s
tr := t*r
tsEqa : t*s = a
trEqb : t*r = b
,
return a proof for ra = sb
.
We use a*b
to denote an AC application. That is, (a*b)*(c*a)
is the term a*a*b*c
.
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Given e := lhs * r
and H : lhs = rhs
, return rhs * r
and the proof of e = rhs * r
.
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The single step of simplifyAC
.
Simplifies an expression e
by either simplifying one argument to the AC operator, or the whole
expression.
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If e
can be simplified by the AC module, return the simplified term and the proof term of the
equality.
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Insert or erase lhs
to the occurrences of arg
on an equality in acR
.
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Insert or erase lhs
to the occurrences of arguments of e
on an equality in acR
.
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Insert lhs
to the occurrences of arguments of e
on an equality in acR
.
Equations
- Mathlib.Tactic.CC.CCM.insertROccs e lhs inLHS = Mathlib.Tactic.CC.CCM.insertEraseROccs e lhs inLHS true
Instances For
Erase lhs
to the occurrences of arguments of e
on an equality in acR
.
Equations
- Mathlib.Tactic.CC.CCM.eraseROccs e lhs inLHS = Mathlib.Tactic.CC.CCM.insertEraseROccs e lhs inLHS false
Instances For
Insert lhs
to the occurrences on an equality in acR
corresponding to the equality
lhs := rhs
.
Equations
- Mathlib.Tactic.CC.CCM.insertRBHSOccs lhs rhs = do Mathlib.Tactic.CC.CCM.insertROccs lhs lhs true Mathlib.Tactic.CC.CCM.insertROccs rhs lhs false
Instances For
Erase lhs
to the occurrences on an equality in acR
corresponding to the equality
lhs := rhs
.
Equations
- Mathlib.Tactic.CC.CCM.eraseRBHSOccs lhs rhs = do Mathlib.Tactic.CC.CCM.eraseROccs lhs lhs true Mathlib.Tactic.CC.CCM.eraseROccs rhs lhs false
Instances For
Insert lhs
to the occurrences of arguments of e
on the right hand side of
an equality in acR
.
Equations
Instances For
Erase lhs
to the occurrences of arguments of e
on the right hand side of
an equality in acR
.
Equations
Instances For
Try to simplify the right hand sides of equalities in acR
by H : lhs = rhs
.
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Try to simplify the left hand sides of equalities in acR
by H : lhs = rhs
.
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Given tsEqa : ts = a
, for each equality trEqb : tr = b
in acR
where
the intersection t
of ts
and tr
is nonempty, let ts = t*s
and tr := t*r
, add a new
equality r*a = s*b
.
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Process the tasks in the acTodo
field.
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Given AC variables e₁
and e₂
which are in the same equivalence class, add the proof of
e₁ = e₂
to the AC module.
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If the root expression of e
is AC variable, add equality to AC module. If not, register the
AC variable to the root entry.
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If e
isn't an AC variable, set e
as an new AC variable.
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Internalize e
so that the AC module can deal with the given expression.
If the expression does not contain an AC operator, or the parent expression
is already processed by internalizeAC
, this operation does nothing.
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The specialized internalizeCore
for applications or literals.
Internalize e
so that the congruence closure can deal with the given expression. Don't forget
to process the tasks in the todo
field later.
Propagate equality from a
and b
to a ↔ b
.
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Propagate equality from a
and b
to a ∧ b
.
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Propagate equality from a
and b
to a ∨ b
.
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Propagate equality from a
to ¬a
.
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Propagate equality from a
and b
to a → b
.
Propagate equality from p
, a
and b
to if p then a else b
.
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Propagate equality from a
and b
to disprove a = b
.
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Propagate equality from subexpressions of e
to e
.
This method is invoked during internalization and eagerly apply basic equivalences for term e
Examples:
In principle, we could mark theorems such as cast_eq
as simplification rules, but this created
problems with the builtin support for cast-introduction in the ematching module in Lean 3.
TODO: check if this is now possible in Lean 4.
Eagerly merging the equivalence classes is also more efficient.
If e
is a subsingleton element, push the equality proof between e
and its canonical form
to the todo list or register e
as the canonical form of itself.
Add an new entry for e
to the congruence closure.
Can we propagate equality from subexpressions of e
to e
?
Equations
Instances For
Remove parents of e
from the congruence table and the symm congruence table, and append
parents to propagate equality, to parentsToPropagate
.
Returns the new value of parentsToPropagate
.
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The fields target
and proof
in e
's entry are encoding a transitivity proof
Let e.rootTarget
and e.rootProof
denote these fields.
e = e.rootTarget := e.rootProof
_ = e.rootTarget.rootTarget := e.rootTarget.rootProof
...
_ = e.root := ...
The transitivity proof eventually reaches the root of the equivalence class.
This method "inverts" the proof. That is, the target
goes from e.root
to e after
we execute it.
Traverse the root
's equivalence class, and for each function application,
collect the function's equivalence class root.
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Reinsert parents of e
to the congruence table and the symm congruence table.
Together with removeParents
, this allows modifying parents of an expression.
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Instances For
Check for integrity of the CCStructure
.
Equations
- Mathlib.Tactic.CC.CCM.checkInvariant = do let __do_lift ← get guard (__do_lift.checkInvariant = true)
Instances For
For each fnRoot
in fnRoots
traverse its parents, and look for a parent prefix that is
in the same equivalence class of the given lambdas.
remark All expressions in lambdas are in the same equivalence class
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Given c
a constructor application, if p
is a projection application (not .proj _ _ _
, but
.app (.const projName _) _
) such that major premise is
equal to c
, then propagate new equality.
Example: if p
is of the form b.fst
, c
is of the form (x, y)
, and b = c
, we add the
equality (x, y).fst = x
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Given a new equality e₁ = e₂
, where e₁
and e₂
are constructor applications.
Implement the following implications:
c a₁ ... aₙ = c b₁ ... bₙ => a₁ = b₁, ..., aₙ = bₙ
c₁ ... = c₂ ... => False
where c
, c₁
and c₂
are constructors
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Given an injective theorem val : type
, whose type
is the form of
a₁ = a₂ ∧ HEq b₁ b₂ ∧ ..
, destruct val
and push equality proofs to the todo list.
Derive contradiction if we can get equality between different values.
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Propagate equality from ¬a
to a
.
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Propagate equality from (a = b) = True
to a = b
.
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Propagate equality from ¬∃ x, p x
to ∀ x, ¬p x
.
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Propagate equality from e
to subexpressions of e
.
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Performs one step in the process when the new equation is added.
Here, H
contains the proof that e₁ = e₂
(if heqProof
is false)
or HEq e₁ e₂
(if heqProof
is true).
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The auxiliary definition for addEqvStep
to flip the input.
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Process the tasks in the todo
field.
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Internalize e
so that the congruence closure can deal with the given expression.
Equations
Instances For
Add H : lhs = rhs
or H : HEq lhs rhs
to the congruence closure. Don't forget to internalize
lhs
and rhs
beforehand.
Equations
- Mathlib.Tactic.CC.CCM.addEqvCore lhs rhs H heqProof = do Mathlib.Tactic.CC.CCM.pushTodo lhs rhs (↑H) heqProof Mathlib.Tactic.CC.CCM.processTodo
Instances For
Add proof : type
to the congruence closure.
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