clean mathematics
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5 changed files with 9 additions and 9 deletions
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@ -352,7 +352,7 @@ lemma finExtractTwo_apply_snd {n : ℕ} (i : Fin n.succ.succ) (j : Fin n.succ) :
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rw [← Equiv.eq_symm_apply]
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simp
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/-- Takes two maps `Fin n → Fin n` and returns the equivelance they form. -/
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/-- Takes two maps `Fin n → Fin n` and returns the equivalence they form. -/
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def finMapToEquiv (f1 : Fin n → Fin m) (f2 : Fin m → Fin n)
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(h : ∀ x, f1 (f2 x) = x := by decide)
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(h' : ∀ x, f2 (f1 x) = x := by decide) : Fin n ≃ Fin m where
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@ -291,11 +291,11 @@ lemma involutionAddEquiv_isSome_image_zero {n : ℕ} :
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## Equivalences of involutions with no fixed points.
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The main aim of thes equivalences is to define `involutionNoFixedZeroEquivProd`.
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The main aim of these equivalences is to define `involutionNoFixedZeroEquivProd`.
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-/
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/-- Fixed point free involutions of `Fin n.succ` can be seperated based on where they sent
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/-- Fixed point free involutions of `Fin n.succ` can be separated based on where they sent
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`0`. -/
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def involutionNoFixedEquivSum {n : ℕ} :
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{f : Fin n.succ → Fin n.succ // Function.Involutive f
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@ -544,7 +544,7 @@ def involutionNoFixedEquivSumSame {n : ℕ} :
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refine Equiv.trans involutionNoFixedEquivSum ?_
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refine Equiv.sigmaCongrRight involutionNoFixedZeroSetEquiv
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/-- Ever fixed-point free involutions of `Fin n.succ.succ` can be decomponsed into a
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/-- Ever fixed-point free involutions of `Fin n.succ.succ` can be decomposed into a
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element of `Fin n.succ` (where `0` is sent) and a fixed-point free involution of
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`Fin n`. -/
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def involutionNoFixedZeroEquivProd {n : ℕ} :
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@ -154,7 +154,7 @@ lemma induction_mod_tmul
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# Dependent type version of PiTensorProduct.tmulEquiv
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-/
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/-- Given two maps `s1` and `s2` whose targets carry an instance of an addative commutative
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/-- Given two maps `s1` and `s2` whose targets carry an instance of an additive commutative
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monoid, the target of the sum of these two maps also carry an instance thereof. -/
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instance : (i : ι1 ⊕ ι2) → AddCommMonoid ((fun i => Sum.elim s1 s2 i) i) := fun i =>
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match i with
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@ -57,7 +57,7 @@ lemma subtype_val_eq_toGL : (Subtype.val : SO3 → Matrix (Fin 3) (Fin 3) ℝ) =
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Units.val ∘ toGL.toFun :=
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rfl
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/-- The inclusino of `SO(3)` into `GL(3,ℝ)` is an injection. -/
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/-- The inclusion of `SO(3)` into `GL(3,ℝ)` is an injection. -/
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lemma toGL_injective : Function.Injective toGL := by
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refine fun A B h ↦ Subtype.eq ?_
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rw [@Units.ext_iff] at h
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@ -17,7 +17,7 @@ closed field, e.g., `ℂ`, is unitarily similar to an upper triangular matrix.
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be decomposed as `A = U * T * star U` where `U` is unitary and `T` is upper triangular.
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- `Matrix.schurTriangulationUnitary` : the unitary matrix `U` as previously stated.
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- `Matrix.schurTriangulation` : the upper triangular matrix `T` as previously stated.
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- Some auxilary definitions are not meant to be used directly, but
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- Some auxiliary definitions are not meant to be used directly, but
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`LinearMap.SchurTriangulationAux.of` contains the main algorithm for the triangulation procedure.
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-/
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@ -124,8 +124,8 @@ end
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Given a linear endomorphism `f` on a non-trivial finite-dimensional vector space `E` over an
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algebraically closed field `𝕜`, one can always pick an eigenvalue `μ` of `f` whose corresponding
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eigenspace `V` is non-trivial. Given that `E` is also an inner product space, let `bV` and `bW` be
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othonormal bases for `V` and `Vᗮ` respectively. Then, the collection of vectors in `bV` and `bW`
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forms an othornomal basis `bE` for `E`, as the direct sum of `V` and `Vᗮ` is an internal
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orthonormal bases for `V` and `Vᗮ` respectively. Then, the collection of vectors in `bV` and `bW`
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forms an orthonormal basis `bE` for `E`, as the direct sum of `V` and `Vᗮ` is an internal
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decomposition of `E`. The matrix representation of `f` with respect to `bE` satisfies
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$$
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\sideset{_\mathrm{bE}}{_\mathrm{bE}}{[f]} =
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