Sesquilinear form #
This file defines the conversion between sesquilinear maps and matrices.
Main definitions #
Matrix.toLinearMap₂given a basis define a bilinear mapMatrix.toLinearMap₂'define the bilinear map onn → RLinearMap.toMatrix₂: calculate the matrix coefficients of a bilinear mapLinearMap.toMatrix₂': calculate the matrix coefficients of a bilinear map onn → R
TODO #
At the moment this is quite a literal port from Matrix.BilinearForm. Everything should be
generalized to fully semi-bilinear forms.
Tags #
Sesquilinear form, Sesquilinear map, matrix, basis
The map from Matrix n n R to bilinear maps on n → R.
This is an auxiliary definition for the equivalence Matrix.toLinearMap₂'.
Equations
- Matrix.toLinearMap₂'Aux σ₁ σ₂ f = LinearMap.mk₂'ₛₗ σ₁ σ₂ (fun (v : n → R₁) (w : m → R₂) => ∑ i : n, ∑ j : m, σ₂ (w j) • σ₁ (v i) • f i j) ⋯ ⋯ ⋯ ⋯
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The linear map from sesquilinear maps to Matrix n m N₂ given an n-indexed basis for M₁
and an m-indexed basis for M₂.
This is an auxiliary definition for the equivalence Matrix.toLinearMapₛₗ₂'.
Equations
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Bilinear maps over n → R #
This section deals with the conversion between matrices and sesquilinear maps on n → R.
The linear equivalence between sesquilinear maps and n × m matrices
Equations
- One or more equations did not get rendered due to their size.
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The linear equivalence between bilinear maps and n × m matrices
Equations
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The linear equivalence between n × n matrices and sesquilinear maps on n → R
Equations
- Matrix.toLinearMapₛₗ₂' R σ₁ σ₂ = (LinearMap.toMatrixₛₗ₂' R).symm
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The linear equivalence between n × n matrices and bilinear maps on n → R
Equations
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Bilinear maps over arbitrary vector spaces #
This section deals with the conversion between matrices and bilinear maps on a module with a fixed basis.
LinearMap.toMatrix₂ b₁ b₂ is the equivalence between R-bilinear maps on M and
n-by-m matrices with entries in R, if b₁ and b₂ are R-bases for M₁ and M₂,
respectively.
Equations
- LinearMap.toMatrix₂ b₁ b₂ = (b₁.equivFun.arrowCongr (b₂.equivFun.arrowCongr (LinearEquiv.refl R N₂))).trans (LinearMap.toMatrix₂' R)
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Matrix.toLinearMap₂ b₁ b₂ is the equivalence between R-bilinear maps on M and
n-by-m matrices with entries in R, if b₁ and b₂ are R-bases for M₁ and M₂,
respectively; this is the reverse direction of LinearMap.toMatrix₂ b₁ b₂.
Equations
- Matrix.toLinearMap₂ b₁ b₂ = (LinearMap.toMatrix₂ b₁ b₂).symm
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Adjoint pairs #
The condition for the matrices A, A' to be an adjoint pair with respect to the square
matrices J, J₃.
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The condition for a square matrix A to be self-adjoint with respect to the square matrix
J.
Equations
- J.IsSelfAdjoint A₁ = J.IsAdjointPair J A₁ A₁
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The condition for a square matrix A to be skew-adjoint with respect to the square matrix
J.
Equations
- J.IsSkewAdjoint A₁ = J.IsAdjointPair J A₁ (-A₁)
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The submodule of pair-self-adjoint matrices with respect to bilinear forms corresponding to
given matrices J, J₂.
Equations
- pairSelfAdjointMatricesSubmodule J J₂ = Submodule.map (↑LinearMap.toMatrix') (((Matrix.toLinearMap₂' R) J).isPairSelfAdjointSubmodule ((Matrix.toLinearMap₂' R) J₂))
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The submodule of self-adjoint matrices with respect to the bilinear form corresponding to
the matrix J.
Equations
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The submodule of skew-adjoint matrices with respect to the bilinear form corresponding to
the matrix J.