This PR implements the proof terms for the new `grind ac` module.
Examples:
```lean
example {α : Sort u} (op : α → α → α) [Std.Associative op] (a b c d : α)
: op a (op b b) = op c d → op c (op d c) = op (op a b) (op b c) := by
grind only
example {α : Sort u} (op : α → α → α) [Std.Associative op] [Std.Commutative op] (a b c d : α)
: op a (op b b) = op d c → op (op b a) (op b c) = op c (op d c) := by
grind only
example {α : Sort u} (op : α → α → α) [Std.Associative op] [Std.Commutative op]
(one : α) [Std.LawfulIdentity op one] (a b c d : α)
: op a (op (op b one) b) = op d c → op (op b a) (op (op b one) c) = op (op c one) (op d c) := by
grind only
```
The `grind ac` module is not complete yet, we still need to implement
critical pair computation and fix the support for idempotent operators.
This PR implements the basic infrastructure for the new procedure
handling AC operators in grind. It already supports normalizing
disequalities. Future PRs will add support for simplification using
equalities, and computing critical pairs. Examples:
```lean
example {α : Sort u} (op : α → α → α) [Std.Associative op] (a b c : α)
: op a (op b c) = op (op a b) c := by
grind only
example {α : Sort u} (op : α → α → α) (u : α) [Std.Associative op] [Std.LawfulIdentity op u] (a b c : α)
: op a (op b c) = op (op a b) (op c u) := by
grind only
example {α : Type u} (op : α → α → α) (u : α) [Std.Associative op] [Std.Commutative op]
[Std.IdempotentOp op] [Std.LawfulIdentity op u] (a b c : α)
: op (op a a) (op b c) = op (op (op b a) (op (op u b) b)) c := by
grind only
example {α} (as bs cs : List α) : as ++ (bs ++ cs) = ((as ++ []) ++ bs) ++ (cs ++ []) := by
grind only
example (a b c : Nat) : max a (max b c) = max (max b 0) (max a c) ∧ min a b = min b a := by
grind only [cases Or]
```
This PR upstreams lemmas about `Rat` from `Mathlib.Data.Rat.Defs` and
`Mathlib.Algebra.Order.Ring.Unbundled.Rat`, specifically enough to get
`Lean.Grind.Field Rat` and `Lean.Grind.OrderedRing Rat`. In addition to
the lemmas, instances for `Inv Rat`, `Pow Rat Nat` and `Pow Rat Int`
have been upstreamed.
---------
Co-authored-by: Kim Morrison <kim@tqft.net>
This PR adds support for detecting associative operators in `grind`. The
new AC module also detects whether the operator is commutative,
idempotent, and whether it has a neutral element. The information is
cached.
This PR improves support for `Fin n` in `grind cutsat` when `n` is not a
numeral. For example, the following goals can now be solved
automatically:
```lean
example (p d : Nat) (n : Fin (p + 1))
: 2 ≤ p → p ≤ d + 1 → d = 1 → n = 0 ∨ n = 1 ∨ n = 2 := by
grind
example (s : Nat) (i j : Fin (s + 1)) (hn : i ≠ j) (hl : ¬i < j) : j < i := by
grind
example {n : Nat} (j : Fin (n + 1)) : j ≤ j := by
grind
example {n : Nat} (x y : Fin ((n + 1) + 1)) (h₂ : ¬x = y) (h : ¬x < y) : y < x := by
grind
```
This PR makes `IsPreorder`, `IsPartialOrder`, `IsLinearPreorder` and
`IsLinearOrder` extend `BEq` and `Ord` as appropriate, adds the
`LawfulOrderBEq` and `LawfulOrderOrd` typeclasses relating `BEq` and
`Ord` to `LE`, and adds many lemmas and instances.
Note: This PR contains a refactoring where `Init.Data.Ord` is moved to
`Init.Data.Ord.Basic`. If I added `Init.Data.Ord` simply importing all
submodules, git would not be able to determine that `Init.Data.Ord` was
renamed to `Init.Data.Ord.Basic`. This could lead to unnecessary merge
conflicts in the future. Hence, I chose the name `Init.Data.OrdRoot`
instead of `Init.Data.Ord` temporarily. After this PR, I will rename
this module back to `Init.Data.Ord` in a separate PR.
(This is a copy of #9430: I will not touch that PR because it currently
allows to debug a CI problem and pushing commits might break the
reproducibility.)
This PR eliminates uses of `intros x y z` (with arguments) and updates
the `intros` docstring to suggest that `intro x y z` should be used
instead. The `intros` tactic is historical, and can be traced all the
way back to Lean 2, when `intro` could only introduce a single
hypothesis. Since 2020, the `intro` tactic has superceded it. The
`intros` tactic (without arguments) is currently still useful.
This PR removes the option `grind +ringNull`. It provided an alternative
proof term construction for the `grind ring` module, but it was less
effective than the default proof construction mode and had effectively
become dead code.
This PR also optimizes semiring normalization proof terms using the
infrastructure added in #9946.
**Remark:** After updating stage0, we can remove several background
theorems from the `Init/Grind` folder.
This PR ensures that `Nat.cast` and `Int.cast` of numerals are
normalized by `grind`.
It also adds a `simp` flag for controlling how bitvector literals are
represented. By default, the bitvector simprocs use `BitVec.ofNat`. This
representation is problematic for the `grind ring` and `grind cutsat`
modules. The new flag allows the use of `OfNat.ofNat` and `Neg.neg` to
represent literals, consistent with how they are represented for other
commutative rings.
Closes#9321
This PR is initially motivated by noticing `Lean.Grind.Preorder.toLE`
appearing in long Mathlib typeclass searches; this change will prevent
these searches. These changes are also helpful preparation for
potentially dropping the custom `Lean.Grind.*` typeclasses, and unifying
with the new typeclasses introduced in #9729.
This PR addresses an outstanding feature in the module system to
automatically mark `let rec` and `where` helper declarations as private
unless they are defined in a public context such as under `@[expose]`.
This PR adds a version of `CommRing.Expr.toPoly` optimized for kernel
reduction. We use this function not only to implement `grind ring`, but
also to interface the ring module with `grind cutsat`.
This PR fixes support for `SMul.smul` in `grind ring`. `SMul.smul`
applications are now normalized. Example:
```lean
example (x : BitVec 2) : x - 2 • x + x = 0 := by
grind
```
This PR add constructors `.intCast k` and `.natCast k` to
`CommRing.Expr`. We need them because terms such as `Nat.cast (R := α)
1` and `(1 : α)` are not definitionally equal. This is pervaise in
Mathlib for the numerals `0` and `1`.
```lean
import Mathlib
example {α : Type} [AddMonoidWithOne α] : Nat.cast (R := α) 0 = (0 : α) := rfl -- not defeq
example {α : Type} [AddMonoidWithOne α] : Nat.cast (R := α) 1 = (1 : α) := rfl -- not defeq
example {α : Type} [AddMonoidWithOne α] : Nat.cast (R := α) 2 = (2 : α) := rfl -- defeq from here
-- Similarly for everything past `AddMonoidWithOne` in the Mathlib hierarchy, e.g. `Ring`.
```
This PR ensures `ite` and `dite` are to selected as E-matching patterns.
They are bad patterns because the then/else branches are only
internalized after `grind` decided whether the condition is
`True`/`False`.
The issue reported by #9572 has been fixed, but the fix exposed another
issue. The patterns for `List.Pairwise` produce an unbounded number of
E-matching instances.
```lean
example (l : List α) : l.Pairwise R := by
grind
```
This PR optimizes the proof terms generated by `grind ring`. For
example, before this PR, the kernel took 2.22 seconds (on a M4 Max) to
type-check the proof in the benchmark `grind_ring_5.lean`; it now takes
only 0.63 seconds.
This PR changes `Lean.Grind.NoNatZeroDivisors` so that it is
parametrised by a `NatModule` instance rather than just a `HMul`
instance. This is sufficiently general for our purposes, and is a
band-aid (~40% improvement) for the performance problems we've been
seeing coming from inference here. The problems observed in Mathlib may
not see much improvement, however.
This PR corrects the changes to `Lean.Grind.Field` made in #9500.
(The lack of examples of fields in the core repository is a problem! I
guess it is likely that for interval arithmetic we will at least need
`Rat` soon.)
This PR adds a `HPow \a Int \a` field to `Lean.Grind.Field`, and
sufficient axioms to connect it to the operations, so that in future we
can reason about exponents in `grind`. To avoid collisions, we also move
the `HPow \a Nat \a` field in `Semiring` from the extends clause to a
field. Finally, we add some failing tests about normalizing exponents.
This PR improves the `evalInt?` function, which is used to evaluate
configuration parameters from the `ToInt` type class. This PR also adds
a new `evalNat?` function for handling the `IsCharP` type class, and
introduces a configuration option:
```
grind (exp := <num>)
```
This option controls the maximum exponent size considered during
expression evaluation. Previously, `evalInt?` used `whnf`, which could
run out of stack space when reducing terms such as `2^1024`.
closes#9427
This PR modifies the encoding from `Nat` to `Int` used in `grind
cutsat`. It is simpler, more extensible, and similar to the generic
`ToInt`. After update stage0, we will be able to delete the leftovers.
This PR replaces the `reduceCtorEq` simproc used in `grind` by a much
more efficient one. The default one use in `simp` is just overhead
because the `grind` normalizer is already normalizing arithmetic.
In a separate PR, we will push performance improvements to the default
`reduceCtorEq`.
This PR optimizes support for `Decidable` instances in `grind`. Because
`Decidable` is a subsingleton, the canonicalizer no longer wastes time
normalizing such instances, a significant performance bottleneck in
benchmarks like `grind_bitvec2.lean`. In addition, the
congruence-closure module now handles `Decidable` instances, and can
solve examples such as:
```lean
example (p q : Prop) (h₁ : Decidable p) (h₂ : Decidable (p ∧ q)) : (p ↔ q) → h₁ ≍ h₂ := by
grind
```
