feat(NumberTheory/EllipticDivisibilitySequence): add some lemmas and grind some proofs

[Multramate]

Also rename odd to neg because odd will be reserved for odd elliptic relations.

---

[github-actions]

PR summary b89e87277a

Import changes for modified files

Dependency changes

File	Base Count	Head Count	Change
Mathlib.NumberTheory.EllipticDivisibilitySequence	751	730	-21 (-2.80%)

Import changes for all files

Files	Import difference
Mathlib.NumberTheory.EllipticDivisibilitySequence	-21

---

Declarations diff (regex)

+ atomRel_abs
+ atomRel_even
+ atomRel_neg
+ atomRel_odd
+ neg_atomRel₁₂
+ neg_atomRel₂₃
+ neg_atomRel₃₄
+ normEDS_atomRel_even
+ normEDS_atomRel_odd
++++ comp

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 b89e872).

• +13 new declarations
• −0 removed declarations

+IsDvdSequence.comp
+IsEllipticDvdSequence.comp
+IsEllipticNet.atomRel_abs
+IsEllipticNet.atomRel_even
+IsEllipticNet.atomRel_neg
+IsEllipticNet.atomRel_odd
+IsEllipticNet.comp
+IsEllipticNet.neg_atomRel₁₂
+IsEllipticNet.neg_atomRel₂₃
+IsEllipticNet.neg_atomRel₃₄
+IsEllipticSequence.comp
+normEDS_atomRel_even
+normEDS_atomRel_odd

---

No changes to strong technical debt.

No changes to weak technical debt.

Current commit b89e87277a
Reference commit 20a3b032e0

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).

[tb65536]

Thanks!

maintainer merge

[github-actions]

🚀 Pull request has been placed on the maintainer queue by tb65536.