[Merged by Bors] - feat(NumberTheory/Primorial): a few simple facts

[thefundamentaltheor3m]

We prove

• the primorial is squarefree
• the prime factors of the primorial are precisely primesLE

We also add that it is non-zero (mere convenience API).

---

[github-actions]

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[github-actions]

PR summary ec26b4ff6d

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference

---

Declarations diff (regex)

+ primeFactors_primorial
+ primorial_ne_zero
+ squarefree_primorial

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 ec26b4f).

• +3 new declarations
• −0 removed declarations

+primeFactors_primorial
+primorial_ne_zero
+squarefree_primorial

---

No changes to strong technical debt.

No changes to weak technical debt.

Current commit ec26b4ff6d
Reference commit 62dc8f267e

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).

[github-actions]

✅ PR Title Formatted Correctly

The title of this PR has been updated to match our commit style conventions.
Thank you!

[loefflerd]

LGTM, just some minor naming issues + golfs

maintainer delegate

[github-actions]

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

[ocfnash]

bors merge

[mathlib-bors]

Pull request successfully merged into master.

Build succeeded:

• ci (staging) / Post-Build Step
• ci (staging) / Test and lint
• ci (staging) / Build
• ci (staging) / Lint style
• ci (staging) / Post-CI job