Skip to content

[Merged by Bors] - feat: torsion of an affine connection#36285

Closed
grunweg wants to merge 19 commits intoleanprover-community:masterfrom
grunweg:covariant-derivatives-torsion
Closed

[Merged by Bors] - feat: torsion of an affine connection#36285
grunweg wants to merge 19 commits intoleanprover-community:masterfrom
grunweg:covariant-derivatives-torsion

Conversation

@grunweg
Copy link
Copy Markdown
Contributor

@grunweg grunweg commented Mar 6, 2026 •
edited
Loading

We define the torsion tensor of an affine connection, i.e. a covariant derivative on the tangent bundle TM of some manifold M. Note that we intentionally do not define the torsion tensor for a connection on a set, as we don't know any actual application of that. (It is easy to add in the future, if need ever arises.)

From the path towards the the Levi-Civita connection and Riemannian geometry.

Co-authored-by: Heather Macbeth 25316162+hrmacbeth@users.noreply.github.com
Co-authored-by: Patrick Massot patrickmassot@free.fr

Open in Gitpod

@grunweg grunweg added the t-differential-geometry Manifolds etc label Mar 6, 2026
@github-actions
Copy link
Copy Markdown

github-actions bot commented Mar 6, 2026 •
edited
Loading

PR summary 4bf038e2f0

Import changes for modified files

No significant changes to the import graph

Import changes for all files
Files Import difference
Mathlib.Geometry.Manifold.VectorBundle.CovariantDerivative.Torsion (new file) 2279

Declarations diff

+ torsionAux
+ torsionAux_tensorial₁
+ torsionAux_tensorial₂
+ torsion_eq_zero_iff
++ torsion
++ torsion_antisymm
++ torsion_apply
++ torsion_apply_eq_extend
++ torsion_self

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.

No changes to technical debt.

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).

@mathlib-dependent-issues mathlib-dependent-issues bot added the blocked-by-other-PR This PR depends on another PR (this label is automatically managed by a bot) label Mar 6, 2026
This was referenced Mar 6, 2026
Open
Open
@mathlib-merge-conflicts
Copy link
Copy Markdown

mathlib-merge-conflicts bot commented Mar 11, 2026

This pull request has conflicts, please merge master and resolve them.

@mathlib-merge-conflicts mathlib-merge-conflicts bot added the merge-conflict The PR has a merge conflict with master, and needs manual merging. (this label is managed by a bot) label Mar 11, 2026
@grunweg grunweg removed blocked-by-other-PR This PR depends on another PR (this label is automatically managed by a bot) merge-conflict The PR has a merge conflict with master, and needs manual merging. (this label is managed by a bot) labels Mar 12, 2026
@mathlib-dependent-issues
Copy link
Copy Markdown

mathlib-dependent-issues bot commented Mar 12, 2026

This PR/issue depends on:

chrisflav
chrisflav reviewed Mar 18, 2026
View reviewed changes
@chrisflav chrisflav added the awaiting-author A reviewer has asked the author a question or requested changes. label Mar 18, 2026
@grunweg grunweg removed the awaiting-author A reviewer has asked the author a question or requested changes. label Mar 18, 2026
@ocfnash
Copy link
Copy Markdown
Contributor

ocfnash commented Mar 18, 2026

bors merge

mathlib-bors bot pushed a commit that referenced this pull request Mar 18, 2026
@grunweg @PatrickMassot @hrmacbeth
feat: torsion of an affine connection (#36285)
83bd0ba 
We define the torsion tensor of an affine connection, i.e. a covariant derivative on the tangent bundle `TM` of some manifold `M`. Note that we intentionally do not define the torsion tensor for a connection on a set, as we don't know any actual application of that. (It is easy to add in the future, if need ever arises.)

From the path towards the the Levi-Civita connection and Riemannian geometry.

Co-authored-by: Heather Macbeth [25316162+hrmacbeth@users.noreply.github.com](mailto:25316162+hrmacbeth@users.noreply.github.com)
Co-authored-by: Patrick Massot <patrickmassot@free.fr>
Co-authored-by: Heather Macbeth <25316162+hrmacbeth@users.noreply.github.com>
@mathlib-triage mathlib-triage bot added the ready-to-merge This PR has been sent to bors. label Mar 18, 2026
@mathlib-bors
Copy link
Copy Markdown
Contributor

mathlib-bors bot commented Mar 18, 2026

Pull request successfully merged into master.

Build succeeded:

@mathlib-bors mathlib-bors bot changed the title feat: torsion of an affine connection [Merged by Bors] - feat: torsion of an affine connection Mar 18, 2026
@mathlib-bors mathlib-bors bot closed this Mar 18, 2026
justus-springer pushed a commit to justus-springer/mathlib4 that referenced this pull request Mar 28, 2026
@grunweg @PatrickMassot
@hrmacbeth @justus-springer
feat: torsion of an affine connection (leanprover-community#36285)
a612e40 
We define the torsion tensor of an affine connection, i.e. a covariant derivative on the tangent bundle `TM` of some manifold `M`. Note that we intentionally do not define the torsion tensor for a connection on a set, as we don't know any actual application of that. (It is easy to add in the future, if need ever arises.)

From the path towards the the Levi-Civita connection and Riemannian geometry.

Co-authored-by: Heather Macbeth [25316162+hrmacbeth@users.noreply.github.com](mailto:25316162+hrmacbeth@users.noreply.github.com)
Co-authored-by: Patrick Massot <patrickmassot@free.fr>
Co-authored-by: Heather Macbeth <25316162+hrmacbeth@users.noreply.github.com>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

@chrisflav chrisflav chrisflav left review comments

Assignees

@ocfnash ocfnash

Labels

ready-to-merge This PR has been sent to bors. t-differential-geometry Manifolds etc

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

5 participants

@grunweg @ocfnash @chrisflav @PatrickMassot @hrmacbeth