[Merged by Bors] - feat(SimpleGraph): weaker condition for paths in acyclic graphs#25814
Closed
vlad902 wants to merge 10 commits intoleanprover-community:masterfrom
Closed
[Merged by Bors] - feat(SimpleGraph): weaker condition for paths in acyclic graphs#25814vlad902 wants to merge 10 commits intoleanprover-community:masterfrom
vlad902 wants to merge 10 commits intoleanprover-community:masterfrom
Conversation
PR summary 0fdf75b47dImport changes for modified filesNo significant changes to the import graph Import changes for all files
|
a28c15a to
31fa249
Compare
vlad902
commented
Jul 14, 2025
be1dda6 to
fd7cd78
Compare
be09e36 to
e2948b3
Compare
adomani
reviewed
Nov 19, 2025
Contributor
|
LGTM other than the comment above |
Contributor
|
bors d+ |
Contributor
|
✌️ vlad902 can now approve this pull request. To approve and merge a pull request, simply reply with |
`IsAcyclic.isPath_iff_chain'` defines a weaker condition for proving that a walk is a path, in particular it shows that rather than all vertices in the support of a walk being distinct, one must only show that consecutive vertices are distinct. This leads to a simple corollary that trails are paths in acyclic graphs.
…eanprover-community#28251) It's not needed anymore.
…nity#28184) Fix typo in the docstring for the Picard–Lindelöf (Cauchy–Lipschitz) theorem: change "intial" to "initial".
e2948b3 to
4690f4f
Compare
Collaborator
Author
|
bors r+ |
mathlib-bors bot
pushed a commit
that referenced
this pull request
Nov 22, 2025
`IsAcyclic.isPath_iff_chain'` defines a weaker condition for proving that a walk is a path, in particular it shows that rather than proving that all vertices in the support of a walk are distinct, one must only show that consecutive edges are distinct (e.g. every other vertex must be distinct.) This leads to a simple corollary that trails are also paths in acyclic graphs. I had a need for this when formalizing Cayley graphs, since this condition maps cleanly onto words in free groups being reduced. Co-authored-by: themathqueen <2497250a@research.gla.ac.uk> Co-authored-by: Dopamineee <austin20050819@gmail.com> Co-authored-by: euprunin <euprunin@users.noreply.github.com>
Contributor
|
Pull request successfully merged into master. Build succeeded: |
alok
added a commit
to alok/mathlib4
that referenced
this pull request
Mar 17, 2026
…lib4 * 'master' of https://github.com/leanprover-community/mathlib4: (3130 commits) feat(SetTheory/ZFC): add `ZFSet.card` (leanprover-community#29365) feat: grind annotations for `choose_spec` (leanprover-community#31927) chore(scripts): update nolints.json (leanprover-community#31975) feat(Analysis): cos (n * π) = (-1) ^ n (leanprover-community#31971) chore: rename `mul_le_mul_right'` to `mul_le_mul_left` (leanprover-community#30242) chore: update Mathlib dependencies 2025-11-22 (leanprover-community#31955) feat(MeasureTheory): ae-measurability notation wrt non-standard sigma-algebra (leanprover-community#31910) doc: add missing spaces around doc code blocks (leanprover-community#31917) chore: update Mathlib dependencies 2025-11-22 (leanprover-community#31945) chore: shortcut instance for `Nat` to be mul-torsion-free (leanprover-community#31027) doc(Topology/Algebra/Algebra): outdated TODO (leanprover-community#31944) feat(EqHaar): add `addHaar_nnreal_smul` (leanprover-community#31922) chore(Algebra): make invertibleInv an instance (leanprover-community#31916) chore(Algebra): change two statements in CubicDiscriminant (leanprover-community#31912) chore(MeasureTheory): mark `map_dirac` as simp (leanprover-community#31909) feat: `LinearOrder` instance for `Empty` (leanprover-community#31889) chore: deprecate all remaining modules in `Analysis/NormedSpace` (leanprover-community#31913) feat(SimpleGraph): weaker condition for paths in acyclic graphs (leanprover-community#25814) chore: do not set `group` when declaring option (leanprover-community#31888) chore: clean up more unused `Decidable*` instances in types (leanprover-community#31934) ...
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
7 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
IsAcyclic.isPath_iff_chain'defines a weaker condition for proving that a walk is a path, in particular it shows that rather than proving that all vertices in the support of a walk are distinct, one must only show that consecutive edges are distinct (e.g. every other vertex must be distinct.) This leads to a simple corollary that trails are also paths in acyclic graphs.I had a need for this when formalizing Cayley graphs, since this condition maps cleanly onto words in free groups being reduced.
This PR continues the work from #25630.
Original PR: #25630