feat(AlgebraicTopology): order relation between simplices of the nerve of a partial order

[joelriou]

This is applied to the characterization of the order relation between simplices of Δ[p] ⊗ Δ[q].

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[github-actions]

PR summary 1c5d0c30c1

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)

+ image_le_image_iff
+ isoNerve_hom_app_obj
+ nerve_ofSimplex_le_ofSimplex_iff
+ ofSimplex_le_ofSimplex_iff
+ preimage_image
+ preimage_monotone
+ range_isoNerve_hom_app_obj

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 -- unavailable)

⚠️ The Mathlib cache for this PR's merge-base isn't on the server (typically a bors-batch intermediate that CI never built). Merge master into this PR and push to refresh.

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No changes to strong technical debt.

No changes to weak technical debt.

Current commit 1c5d0c30c1
Reference commit 5e1cacbae2

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).