[Merged by Bors] - fix(Tactic/Ring): sort terms when evaluating nested powers#37494
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FLDutchmann wants to merge 3 commits intoleanprover-community:masterfrom
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[Merged by Bors] - fix(Tactic/Ring): sort terms when evaluating nested powers#37494FLDutchmann wants to merge 3 commits intoleanprover-community:masterfrom
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PR summary cbbd8c9b8bImport changes for modified filesNo significant changes to the import graph Import changes for all files
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You can run this locally as follows## summary with just the declaration names:
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./scripts/pr_summary/declarations_diff.sh long <optional_commit>The doc-module for No changes to technical debt.You can run this locally as
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Benchmark results for 21266de against cbbd8c9 are in. There are no significant changes. @FLDutchmann
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Apr 1, 2026
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Seems reasonable, thanks! Let me only maintainer merge this since I'm not an expert on ring.
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🚀 Pull request has been placed on the maintainer queue by grunweg. |
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`ring` currently misorders the terms in a product when evaluating nested powers. When evaluating e.g. `(x^a*x)^b` where `x` is an atom, it returns `x^(a*b)*x^b` even if `b` is supposed to come before `a*b` in the ordering on `ExProd`s. We fix this by running `evalMulProd` instead of using the `.mul` constructor directly. This in effect does an insertion sort on the terms in the `ExProd`s. We do a similar thing when evaluating multiplication. ``` /-- error: ring failed, ring expressions not equal a : ℚ m n : ℕ ⊢ a ^ n * a ^ (m * n) = a ^ (m * n) * a ^ n -/ #guard_msgs in example (a : ℚ) (m n : ℕ) : (a ^ (m + 1)) ^ n = a ^ (n * (m + 1)) := by ring1 ```
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`ring` currently misorders the terms in a product when evaluating nested powers. When evaluating e.g. `(x^a*x)^b` where `x` is an atom, it returns `x^(a*b)*x^b` even if `b` is supposed to come before `a*b` in the ordering on `ExProd`s. We fix this by running `evalMulProd` instead of using the `.mul` constructor directly. This in effect does an insertion sort on the terms in the `ExProd`s. We do a similar thing when evaluating multiplication. ``` /-- error: ring failed, ring expressions not equal a : ℚ m n : ℕ ⊢ a ^ n * a ^ (m * n) = a ^ (m * n) * a ^ n -/ #guard_msgs in example (a : ℚ) (m n : ℕ) : (a ^ (m + 1)) ^ n = a ^ (n * (m + 1)) := by ring1 ```
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Pull request successfully merged into master. Build succeeded: |
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ringcurrently misorders the terms in a product when evaluating nested powers. When evaluating e.g.(x^a*x)^bwherexis an atom, it returnsx^(a*b)*x^beven ifbis supposed to come beforea*bin the ordering onExProds.We fix this by running
evalMulProdinstead of using the.mulconstructor directly. This in effect does an insertion sort on the terms in theExProds. We do a similar thing when evaluating multiplication.This bug was pointed out to me by @Multramate
The fix in this PR was written and investigated with the help of Claude code.