feat(AlgebraicTopology/SimplicialSet): evaluation on subcomplexes

[joelriou]

In this PR, given a simplicial set X and j : SimplexCategoryᵒᵖ, we define a functor evaluation X j : X.Subcomplex ⥤ Set (X.obj j), and use it to show that the functor Subcomplex.toSSetFunctor which sends a subcomplex of X to the corresponding simplicial set preserves filtered colimits.

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[github-actions]

PR summary 82670e855c

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference
Mathlib.AlgebraicTopology.SimplicialSet.SubcomplexEvaluation (new file)	886

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Declarations diff

+ evaluation
+ instance {J : Type*} [Category J] {X : SSet.{u}} [IsFilteredOrEmpty J] :
+ ofSimplex_map
+ preimage_comp
+ preimage_ι

You can run this locally as follows

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

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

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

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Increase in tech debt: (relative, absolute) = (1.00, 0.00)

Current number	Change	Type
7343	1	backward.isDefEq

Current commit 16878be3e3
Reference commit 82670e855c

You can run this locally as

./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).