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Diff — Linear map

Revision #1367 → #2114 · back to history

modifiedPreservation of linear combinationsee03229d3d5e
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mathlib.moduleMathlib.Algebra.Module.LinearMap.DefsMathlib.Algebra.BigOperators.Group.Finset.Defs
noteLinear maps preserve finite sums (via `map_sum`) and scalar multiples (`map_smul`), hence preserve linear combinations.Linear maps preserve finite sums (via `map_sum`) and scalar multiples (`LinearMap.map_smul`), hence preserve linear combinations.
modifiedUnique map of given form is linear6d8e2926fb03
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mathlib.moduleMathlib.Algebra.Module.LinearMap.DefsMathlib.Algebra.Module.LinearMap.End
modifiedLine through the originfaa2c189d173
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mathlib.moduleMathlib.Algebra.Algebra.BilinearMathlib.LinearAlgebra.BilinearMap
modifiedHomothety is linearf9915710617e
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mathlib.moduleMathlib.Algebra.Algebra.BilinearMathlib.LinearAlgebra.BilinearMap
modifiedIsometry on real normed spaces8a22b9781597
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mathlib.match_kindgeneralizationspecial_case
note`LinearIsometry` formalizes norm-preserving linear maps between normed spaces.`LinearIsometry` bundles norm-preserving linear maps, but the Wikipedia claim is the Mazur–Ulam-style converse ('an isometry sending 0 to 0 is linear'), which is the relevant direction here.
provenanceaiai-moderated
statusformalizedpartial
modifiedDefinite integral is linear5af80902be1f
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mathlib.moduleMathlib.MeasureTheory.Integral.IntervalIntegralMathlib.MeasureTheory.Integral.IntervalIntegral.Basic
modifiedComponent scaling is linearc36c4c4526d4
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mathlib.moduleMathlib.Algebra.Module.LinearMap.DefsMathlib.Algebra.Module.LinearMap.End
modifiedLinear extension7061b172a30f
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mathlib.declBasis.constrModule.Basis.constr
noteMathlib has `Basis.constr` to extend a function on a basis to a linear map, but no general 'linear extension of a function on a subset' definition matching the Wikipedia notion.Mathlib has `Module.Basis.constr` to extend a function on a basis to a linear map, but no general 'linear extension of a function on a subset' definition matching the Wikipedia notion.
modifiedLinearly independent set extensionc6faabcd79f7
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mathlib.declBasis.constrModule.Basis.constr
note`Basis.constr` lets any function on a basis be linearly extended; together with extension of a linearly independent set to a basis, this gives the Wikipedia statement.`Module.Basis.constr` lets any function on a basis be linearly extended; together with extension of a linearly independent set to a basis, this gives the Wikipedia statement.
modifiedRotation by 90 degrees counterclockwise8ebedc52c522
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mathlib.moduleMathlib.Analysis.Complex.IsometryMathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic
modifiedRotation by angle θ53e1390769b9
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mathlib.moduleMathlib.Analysis.Complex.IsometryMathlib.LinearAlgebra.Matrix.GeneralLinearGroup.Basic
modifiedScaling by 26ff186352fa7
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mathlib.moduleMathlib.Algebra.Algebra.BilinearMathlib.LinearAlgebra.BilinearMap
modifiedSet of linear maps forms a vector space52fa55b31782
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mathlib.declLinearMap.instModuleLinearMap.module
noteMathlib gives `M →ₛₗ[σ] N` a `Module` instance, making `Hom(V,W)` a vector space.Mathlib gives `M →ₛₗ[σ] N` a `Module` instance via `LinearMap.module`, making `Hom(V,W)` a vector space.
modifiedAutomorphism and automorphism groupa6b9771c4fd9
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mathlib.moduleMathlib.Algebra.Module.LinearMap.GeneralLinearGroupMathlib.LinearAlgebra.GeneralLinearGroup.Basic
modifiedRank and nullitycd17badeb70e
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mathlib.moduleMathlib.LinearAlgebra.Dimension.ConstructionsMathlib.LinearAlgebra.Dimension.LinearMap
modifiedCokernel2c4ad85ceed0
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mathlib.declSubmodule.QuotientSubmodule.hasQuotient
mathlib.moduleMathlib.LinearAlgebra.Quotient.BasicMathlib.LinearAlgebra.Quotient.Defs
noteThe cokernel is `M₂ ⧸ LinearMap.range f`, expressed using `Submodule` quotients; explicitly used in `Mathlib.Algebra.Module.Presentation.Cokernel`.The cokernel is `M₂ ⧸ LinearMap.range f`, expressed using the `Submodule.hasQuotient` quotient construction.
modifiedCokernel exact sequence6274bb1c4c62
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mathlib.declShortComplex.cokernelSequenceCategoryTheory.ShortComplex.Exact
noteExact-sequence formalism (e.g., `ShortComplex`/`cokernelSequence`) covers this in general categorical setting; no direct Wikipedia-style statement for modules.Exact-sequence formalism via `CategoryTheory.ShortComplex.Exact` covers this in the general categorical setting; no direct Wikipedia-style statement for modules.
modifiedNilpotent, idempotent, scaling endomorphisms38e860ccbb11
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mathlib.moduleMathlib.RingTheory.Nilpotent.DefsMathlib.Algebra.GroupWithZero.Basic
modifiedContinuity equals boundednessc6f5d628daad
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mathlib.declLinearMap.continuous_iff_isBoundedIsBoundedLinearMap.isLinearMap_and_continuous_iff_isBoundedLinearMap
noteMathlib's `isLinearMap_and_continuous_iff_isBoundedLinearMap` (and related `LinearMap.continuous_of_bound`) state continuity equivalent to boundedness.`IsBoundedLinearMap.isLinearMap_and_continuous_iff_isBoundedLinearMap` states that a function is linear and continuous iff it is a bounded linear map.
addedLinear maps send subspaces to subspaces8f89d2d1820a
addedCategory of vector spaces / modules54e820e514d2
addedAutomorphism group as units of endomorphism ringccc4bdf6776a
addedAutomorphism group isomorphic to GLₙ07f5bdf6d168