460b3c3e43
This PR fixes an issue where `grind` failed to prove `f ≠ 0` from `f * r ≠ 0` when using `Lean.Grind.CommSemiring`, but succeeded with `Lean.Grind.Semiring`. The `propagateMul` propagator handles `0 * a = 0` and `a * 0 = 0` rules for semirings that don't have full ring support in grind. Previously, `CommSemiring` was excluded because it uses a ring envelope for normalization, but that approach doesn't propagate these equalities back to the original terms. Now `CommSemiring` also uses `propagateMul`. Reported as https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/Grind.20failure.20for.20CommSemiring.2C.20not.20Semiring 🤖 Prepared with Claude Code --------- Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
35 lines
1.1 KiB
Text
35 lines
1.1 KiB
Text
/-!
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# Tests for grind with CommSemiring
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These tests verify that grind properly propagates `0 * a = 0` and `a * 0 = 0`
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for CommSemiring types, not just Semiring types.
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See: https://leanprover.zulipchat.com/#narrow/channel/270676-lean4/topic/Grind.20failure.20for.20CommSemiring.2C.20not.20Semiring
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-/
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-- Basic test with Semiring
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example {R : Type} [Lean.Grind.Semiring R] (f r : R) (hg : f * r ≠ 0) :
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f ≠ 0 := by
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grind
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-- Same test should also work with CommSemiring
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example {R : Type} [Lean.Grind.CommSemiring R] (f r : R) (hg : f * r ≠ 0) :
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f ≠ 0 := by
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grind
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-- Symmetric case: r * f ≠ 0 implies f ≠ 0
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example {R : Type} [Lean.Grind.CommSemiring R] (f r : R) (hg : r * f ≠ 0) :
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f ≠ 0 := by
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grind
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-- Both factors must be nonzero
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example {R : Type} [Lean.Grind.CommSemiring R] (f r : R) (hg : f * r ≠ 0) :
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f ≠ 0 ∧ r ≠ 0 := by
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grind
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-- mul_one and one_mul propagation
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example {R : Type} [Lean.Grind.CommSemiring R] (f g : R) (h1 : 1 * f = g) (h2 : g ≠ f) : False := by
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grind
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example {R : Type} [Lean.Grind.CommSemiring R] (f g : R) (h1 : f * 1 = g) (h2 : g ≠ f) : False := by
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grind
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