chore(Logic/Relation): golf using grind

[SnirBroshi]

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[github-actions]

PR summary 87e8eb9264

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 (regex)

No declarations were harmed in the making of this PR! 🐙

You can run this locally as follows

## from your `mathlib4` directory:
git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci

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

## more verbose report:
../mathlib-ci/scripts/pr_summary/declarations_diff.sh long <optional_commit>

The doc-module for scripts/pr_summary/declarations_diff.sh in the mathlib-ci repository contains some details about this script.

Declarations diff (Lean)

✅ Lean-aware diff — post-build, computed from the Lean environment (commit 87e8eb9).

• +0 new declarations
• −0 removed declarations

No declaration differences.

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No changes to strong technical debt.

No changes to weak technical debt.

Current commit 87e8eb9264
Reference commit c368140668

This script lives in the mathlib-ci repository. To run it locally, from your mathlib4 directory:

git clone https://github.com/leanprover-community/mathlib-ci.git ../mathlib-ci
../mathlib-ci/scripts/reporting/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).

[themathqueen]

!radar

[leanprover-radar]

Benchmark results for 87e8eb9 against c368140 are in. No significant results found. @themathqueen

• 🟥 build//instructions: +41.6G (+0.03%)

Small changes (1🟥)

• 🟥 build/module/Mathlib.Logic.Relation//instructions: +1.3G (+6.60%)

[themathqueen]

Suggested change

	⟨by intro h; induction h <;> grind [Equivalence], .rel a b⟩
	⟨fun h ↦ by induction h <;> grind [Equivalence], .rel a b⟩

[grunweg]

Here and in your other grind golfing PR: can you add a performance comparison (look at euprunin's PRs for an example) please? Thanks!

[chenson2018]

At the most extreme the whole proof could even be

induction ab with grind [→ cases_head, Relator.RightUnique]

though some compromise inbetween along the spectrum of readability/performance is probably preferable