[Merged by Bors] - feat(Data/Matroid/Circuit): fundamental circuits and extensionality #21145
[Merged by Bors] - feat(Data/Matroid/Circuit): fundamental circuits and extensionality #21145
Conversation
PR summary db9c0ecac7Import changes for modified filesNo significant changes to the import graph Import changes for all files
|
Thanks for the very helpful review! |
b-mehta
left a comment
There was a problem hiding this comment.
A couple more things I noticed on my final pass. Thank you!
bors d+
|
✌️ apnelson1 can now approve this pull request. To approve and merge a pull request, simply reply with |
Co-authored-by: Bhavik Mehta <bhavikmehta8@gmail.com>
|
bors r+ |
…21145) We define the fundamental circuit in a matroid for a set `I` and an element `e`, then use it to show that dependent sets all contain circuits, and a circuit-based extensionality lemma.
|
Pull request successfully merged into master. Build succeeded: |
* origin/master: (294 commits) feat: equalizers and coequalizers in the category of ind-objects (#21139) doc: turn more links to Stacks into `@[stacks]` tags (#21135) feat(Asymptotics): prove `IsLittleOTVS.add` (#20578) feat(Algebra/Polynomial): `Polynomial.aeval` for product algebras (#21062) chore: import Std in Mathlib.lean (#21126) feat(Data/Matroid/Circuit): fundamental circuits and extensionality (#21145) feat(CategoryTheory/Endofunctor): prove the dual form of Lambek's Lemma on terminal coalgebra (#21140) feat(SetTheory/Game/PGame): rewrite left moves of `-x` as right moves of `x` under binders (#21109) feat(RingTheory/Localization/Pi): localization of a finite direct product is a product of localizations (#19042) doc: fixed notation error in customizing category composition (#21132) feat(Matrix): more lemmas for `PEquiv.toMatrix` (#21143) chore(SupIndep): speedup the `Decidable` instance (#21114) fix(CI): use `Elab.async=false` for late importers workflow (#21147) feat(Topology/Algebra/Indicator): indicator of a clopen is continuous (#20687) feat(Data/Matroid/Rank/Cardinal): Cardinality-valued rank function (#20921) feat(Algebra): `Pi.single_induction` (#21141) chore(BigOperators/Fin): golf a proof (#21131) feat: generalize tangent cone lemmas to TVS (#20859) feat(CategoryTheory): `Comma.snd L R` is final if `R` is final and domains are filtered (#21136) refactor: unapply matrix lemmas (#21091) chore(Algebra/Category): `erw` -> `rw` (#21130) feat(CategoryTheory): filteredness of Comma catgories given finality of one of the functors (#21128) feat(Algebra/Category): `ConcreteCategory` instance for `ModuleCat` (#21125) feat: PSum of finite sorts is finite (#20285) feat: inequality on the integral of a convex function of a RN derivative (#21093) feat: `(v +ᵥ s) -ᵥ (v +ᵥ t) = s -ᵥ t` (#21058) chore: rename the fact that `(∀ a < a₁, a ≤ a₂) ↔ a₁ ≤ a₂` in a dense order (#20317) feat: a `RelHom` preserves directedness (#20080) feat(Combinatorics/SimpleGraph): add definitions and theorems about the coloring of sum graphs (#18677) chore(Data/Matrix/PEquiv): clean up names (#21108) feat(Algebra/Category): `ConcreteCategory` instances for rings (#20815) feat: define Descriptive.Tree (#18763) chore(Data/Complex/Exponential): split trig functions to new file (#21075) feat(Logic/IsEmpty/Relator): empty on sides (#20319) feat(Algebra/Category): `ConcreteCategory` instance for `AlgebraCat` (#21121) feat(NumberTheory/LSeries): results involving partial sums of coefficients (part 1) (#20661) feat(RingTheory/LaurentSeries): add algebraEquiv (#21004) chore(SetTheory/Game/Impartial): golf two proofs (#21074) feat(CategoryTheory/Subpresheaf): preimage/image/range of subpresheaves (#21047) feat(RingTheory/IntegralClosure): `Algebra.IsIntegral` transfers via surjective homomorphisms (#21023) feat(`InformationTheory/Hamming`): Add AddGroup instances (#20994) feat(RingTheory/IntegralClosure): prove `Module.Finite R (adjoin R S)` for finite set `S` of integral elements (#20970) feat(RingTheory/Artinian): `IsUnit a` iff `a ∈ R⁰` for an artinian ring `R` (#21084) feat: separating set in the category of ind-objects (#21082) feat: derivWithin lemmas (#21092) chore(Fintype): golf a proof (#21113) chore: golf using `funext₂` (#21106) chore(Algebra/Group/Submonoid/Operations): move instances to new file (#21067) doc(Algebra/BigOperators/Fin): change 'product' to 'sum' in doc-string of additivised declarations (#21101) doc(ComputeDegree): typos (#21095) ...
) The definition of fundamental circuits in #21145 was suboptimal, in that its junk values were unstable. We slightly modify the definition so that the fundamental circuit of a non-element `e` of the ground set is a singleton `{e}`. This removes assumptions from a couple of existing lemmas, and crucially makes the useful lemma `Matroid.fundCircuit_restrict_univ` true, where it wasn't before.
* polynomial-sequences: (308 commits) Use the lemma we already added. Minor reordering. This is true even for the trivial ring. Also add the lt versions and the other inj lemma. Also add the basis ne versions. This seems also like it should be simp. Back to sorry free. And the natDegree version. feat: equalizers and coequalizers in the category of ind-objects (#21139) doc: turn more links to Stacks into `@[stacks]` tags (#21135) feat(Asymptotics): prove `IsLittleOTVS.add` (#20578) feat(Algebra/Polynomial): `Polynomial.aeval` for product algebras (#21062) chore: import Std in Mathlib.lean (#21126) feat(Data/Matroid/Circuit): fundamental circuits and extensionality (#21145) feat(CategoryTheory/Endofunctor): prove the dual form of Lambek's Lemma on terminal coalgebra (#21140) feat(SetTheory/Game/PGame): rewrite left moves of `-x` as right moves of `x` under binders (#21109) feat(RingTheory/Localization/Pi): localization of a finite direct product is a product of localizations (#19042) doc: fixed notation error in customizing category composition (#21132) feat(Matrix): more lemmas for `PEquiv.toMatrix` (#21143) chore(SupIndep): speedup the `Decidable` instance (#21114) fix(CI): use `Elab.async=false` for late importers workflow (#21147) feat(Topology/Algebra/Indicator): indicator of a clopen is continuous (#20687) feat(Data/Matroid/Rank/Cardinal): Cardinality-valued rank function (#20921) feat(Algebra): `Pi.single_induction` (#21141) chore(BigOperators/Fin): golf a proof (#21131) feat: generalize tangent cone lemmas to TVS (#20859) feat(CategoryTheory): `Comma.snd L R` is final if `R` is final and domains are filtered (#21136) refactor: unapply matrix lemmas (#21091) chore(Algebra/Category): `erw` -> `rw` (#21130) feat(CategoryTheory): filteredness of Comma catgories given finality of one of the functors (#21128) feat(Algebra/Category): `ConcreteCategory` instance for `ModuleCat` (#21125) feat: PSum of finite sorts is finite (#20285) feat: inequality on the integral of a convex function of a RN derivative (#21093) feat: `(v +ᵥ s) -ᵥ (v +ᵥ t) = s -ᵥ t` (#21058) chore: rename the fact that `(∀ a < a₁, a ≤ a₂) ↔ a₁ ≤ a₂` in a dense order (#20317) feat: a `RelHom` preserves directedness (#20080) feat(Combinatorics/SimpleGraph): add definitions and theorems about the coloring of sum graphs (#18677) chore(Data/Matrix/PEquiv): clean up names (#21108) feat(Algebra/Category): `ConcreteCategory` instances for rings (#20815) feat: define Descriptive.Tree (#18763) chore(Data/Complex/Exponential): split trig functions to new file (#21075) feat(Logic/IsEmpty/Relator): empty on sides (#20319) feat(Algebra/Category): `ConcreteCategory` instance for `AlgebraCat` (#21121) feat(NumberTheory/LSeries): results involving partial sums of coefficients (part 1) (#20661) feat(RingTheory/LaurentSeries): add algebraEquiv (#21004) chore(SetTheory/Game/Impartial): golf two proofs (#21074) feat(CategoryTheory/Subpresheaf): preimage/image/range of subpresheaves (#21047) feat(RingTheory/IntegralClosure): `Algebra.IsIntegral` transfers via surjective homomorphisms (#21023) feat(`InformationTheory/Hamming`): Add AddGroup instances (#20994) feat(RingTheory/IntegralClosure): prove `Module.Finite R (adjoin R S)` for finite set `S` of integral elements (#20970) ...
) The definition of fundamental circuits in #21145 was suboptimal, in that its junk values were unstable. We slightly modify the definition so that the fundamental circuit of a non-element `e` of the ground set is a singleton `{e}`. This removes assumptions from a couple of existing lemmas, and crucially makes the useful lemma `Matroid.fundCircuit_restrict_univ` true, where it wasn't before.
We define the fundamental circuit in a matroid for a set
Iand an elemente, then use it to show that dependent sets all contain circuits, and a circuit-based extensionality lemma.