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Diff — Fractal

Revision #1238 → #1721 · back to history

modifiedFractal scaling by non-integer power8c1fb164c0e2
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note`hausdorffMeasure_smul₀` proves μH[d](r•s)=‖r‖^d•μH[d] s for real d, formalizing how d-dimensional content scales by a possibly non-integer power, but without the 'fractal' framing.`hausdorffMeasure_smul₀` proves μH[d](r•s)=‖r‖^d•μH[d] s for real d, formalizing how d-dimensional content scales by a possibly non-integer power, without the 'fractal' framing.
modifiedFractal dimensionf809af8256c7
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mathlib.declMeasureTheory.dimHdimH
note`MeasureTheory.dimH` is the Hausdorff dimension, the rigorous form of the fractal/scaling dimension defined for arbitrary sets.`dimH` is the Hausdorff dimension, the rigorous form of the fractal/scaling dimension defined for arbitrary sets in an (e)metric space.
modifiedMandelbrot 1982 definition83876923ae70
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mathlib.declMeasureTheory.dimHdimH
modifiedRep-tiling of a squarec397142bc27c
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mathlib.declMeasureTheory.dimH_univ_eq_finrankReal.dimH_univ_eq_finrank
noteA square's dimension being 2 follows from `dimH_univ_eq_finrank` (and area scales by r² via `hausdorffMeasure_smul₀`), but rep-tiling is not formalized.A square's dimension being 2 follows from `Real.dimH_univ_eq_finrank` (and area scales by r² via `hausdorffMeasure_smul₀`), but rep-tiling is not formalized.
modifiedRep-tiling rule for n-dimensional objects8a3adce7e68b
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noteThe scaling law μH[n](r•s)=r^n·μH[n] s captures the n-dimensional scaling content, but the rep-tiling/piece-counting formulation is absent.The scaling law μH[n](r•s)=‖r‖^n·μH[n] s captures the n-dimensional scaling content, but the rep-tiling/piece-counting formulation is absent.
modifiedFractal dimension of the Koch curveac6e362fde2f
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noteThe Koch curve and its Hausdorff dimension log 4/log 3 are not formalized (Snowflaking.lean only mentions the Koch snowflake in prose).The Koch curve and its Hausdorff dimension log 4/log 3 are not formalized in Mathlib.
modifiedWeierstrass function7ba90a9ff3a1
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noteA continuous-everywhere, nowhere-differentiable Weierstrass function is fully formalized, though it lives in the Counterexamples directory rather than the core Mathlib library.A continuous-everywhere, nowhere-differentiable Weierstrass-type function is formalized, though it lives in the Counterexamples directory rather than core Mathlib.
modifiedCantor sets61202df29c0a
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note`cantorSet` is the ternary Cantor set defined as ⋂ₙ preCantorSet n on the real line.`cantorSet` is the ternary Cantor set defined on the real line in `Mathlib.Topology.Instances.CantorSet`.
modifiedNon-integer (Hausdorff) dimension2b053f356136
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mathlib.declMeasureTheory.dimHdimH
note`MeasureTheory.dimH` takes values in ℝ≥0∞ and may be non-integer, exactly the Hausdorff dimension allowing fractional dimensions.`dimH` takes values in ℝ≥0∞ and may be non-integer, exactly the Hausdorff dimension allowing fractional dimensions.
modifiedHausdorff–Besicovitch dimension exceeds topologicala39b2cc55465
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mathlib.declMeasureTheory.dimHdimH
noteBoth `dimH` and a topological (`smallInductiveDimension`) dimension exist, but Mathlib has no predicate for dimH exceeding topological dimension.Both `dimH` and a topological dimension (`smallInductiveDimension`) exist, but Mathlib has no predicate for dimH exceeding topological dimension.
addedMandelbrot setb3673e77950e
addedMenger sponge2e18fa0d753c
addedTopological dimensionf9e75904b3b4
addedHausdorff dimension links fractals to measure theoryc20614388e22
addedSierpiński triangle162dd5ba8c11
addedSierpinski carpet0be9e975a60e
addedBrownian motion / Wiener process72bd59b06445
addedJulia setd6d0b0e0f18e