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Diff — Geometric group theory

Revision #1262 → #2286 · back to history

addedGroup presentation2846f9441d80
modifiedHyperbolic groupa9cb61ae7102
FieldFrom #1262To #2286
noteMathlib's only 'hyperbolic' references are to hyperbolic functions/geometry, not Gromov-hyperbolic groups.Mathlib's only 'hyperbolic' references are to hyperbolic functions/geometry and `Matrix.IsHyperbolic`, not Gromov-hyperbolic groups.
modifiedGromov's polynomial growth theorema65f1757253b
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noteNo formalization of group growth or Gromov's theorem exists (the only 'polynomial growth' is Akra–Bazzi function asymptotics).No formalization of group growth or Gromov's theorem exists in Mathlib.
modifiedMostow rigidity theoreme09a5cb295ea
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noteMostow rigidity is not present in Mathlib.Mostow rigidity is not present in Mathlib (loogle returns zero hits for 'Mostow').
addedDehn function / isoperimetric function7214b9441a2e
addedKazhdan's property (T)f7c76292a9d0
addedBass–Serre theory5519795f7242
modifiedAmenable groups53e3668e776c
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noteMathlib has Følner-filter amenability (`IsFoelner.amenable`) but, per its own docstring, no standalone definition of an amenable group.Mathlib has Følner-filter amenability (`IsFoelner.amenable`) but no standalone definition of an amenable group as a class.
modifiedOuter automorphism groups Out(Fn)0d03171d0742
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noteMathlib has `MulAut` and `FreeGroup` but no outer automorphism group (Aut/Inn) construction.Mathlib has `MulAut` and `FreeGroup` but no `OuterAut`/Out(Fn) construction (loogle returns zero 'OuterAut' hits).
modifiedBraid groupsb0964e3ff52b
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noteMathlib's 'braid' references are to braided monoidal categories, not the braid groups.Mathlib's 'braid'/'braiding' references are all to braided monoidal categories, not the Artin braid groups Bn.
modifiedBaumslag–Solitar groupsf3939a5a2244
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noteBaumslag–Solitar groups are HNN extensions of ℤ; Mathlib has the general `HNNExtension` construction but not these specific groups.Baumslag–Solitar groups are HNN extensions of ℤ; Mathlib has the general `HNNExtension` construction but not these specific groups (loogle returns zero 'BaumslagSolitar' hits).
modifiedGrigorchuk group8f80adcf2e64
FieldFrom #1262To #2286
noteThe Grigorchuk group is not formalized in Mathlib.The Grigorchuk group is not formalized in Mathlib (loogle returns zero 'Grigorchuk' hits).