[Merged by Bors] - chore(Polynomial/*): avoid simp lemma that introduces Nat subtraction

[jcommelin]

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[github-actions]

PR summary 62ab752f9c

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

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Declarations diff

+ derivative_X_pow_succ
+ derivative_monomial_succ

You can run this locally as follows

## summary with just the declaration names:
./scripts/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/declarations_diff.sh long <optional_commit>

The doc-module for script/declarations_diff.sh contains some details about this script.

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No changes to technical debt.

You can run this locally as

./scripts/technical-debt-metrics.sh pr_summary

• The relative value is the weighted sum of the differences with weight given by the inverse of the current value of the statistic.
• The absolute value is the relative value divided by the total sum of the inverses of the current values (i.e. the weighted average of the differences).

[Vierkantor]

(I checked that the n = 0 cases are indeed still simplified correctly.)

Is there a specific example you can point to that gets a clear improvement? Or is it more of a general principle to avoid nat subtraction?

I suppose either way I'm not going to oppose this change, it makes simp slightly less powerful but it doesn't actually seem to have that big of an impact overall.

bors r+

[mathlib-bors]

Pull request successfully merged into master.

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