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Physlib.Mathematics.LinearMaps

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definition

Homogeneous quadratic equation f:VQf: V \to \mathbb{Q} satisfying f(av)=a2f(v)f(a \cdot v) = a^2 f(v)

#HomogeneousQuadratic

Let VV be a vector space (or module) over the rational numbers Q\mathbb{Q}. A homogeneous quadratic equation is a map f:VQf : V \to \mathbb{Q} such that for any scalar aQa \in \mathbb{Q} and any vector vVv \in V, the function satisfies the homogeneity property f(av)=a2f(v)f(a \cdot v) = a^2 f(v).

instance

Homogeneous quadratic equation as a function \( f: V \to \mathbb{Q} \)

#instFun

This instance allows a homogeneous quadratic equation \( f \in \text{HomogeneousQuadratic } V \) to be treated as a function from a vector space \( V \) (over \( \mathbb{Q} \)) to the rational numbers \( \mathbb{Q} \). It provides the mechanism to evaluate the equation at a vector \( v \in V \) to produce the value \( f(v) \in \mathbb{Q} \).

theorem

f(aS)=a2f(S)f(a \cdot S) = a^2 f(S) for a homogeneous quadratic map ff

#map_smul

Let VV be a vector space (or module) over the rational numbers Q\mathbb{Q}. For any homogeneous quadratic map f:VQf: V \to \mathbb{Q}, any scalar aQa \in \mathbb{Q}, and any vector SVS \in V, the identity f(aS)=a2f(S)f(a \cdot S) = a^2 f(S) holds.

instance

Symmetric bilinear form as a function V(VQ)V \to (V \to_\ell \mathbb{Q})

#instFun

Let VV be a vector space over the rational numbers Q\mathbb{Q}. This instance allows a symmetric bilinear form fBiLinearSymm Vf \in \text{BiLinearSymm } V to be treated as a function from VV to the space of Q\mathbb{Q}-linear maps from VV to Q\mathbb{Q} (the dual space). Specifically, for any vector vVv \in V, the evaluation f(v)f(v) is a linear functional such that for any wVw \in V, f(v)(w)f(v)(w) returns a value in Q\mathbb{Q}.

definition

Symmetric bilinear map from first-factor linearity and f(S,T)=f(T,S)f(S, T) = f(T, S)

#mk₂

Let VV be a vector space over the rational numbers Q\mathbb{Q}. Given a function f:V×VQf : V \times V \to \mathbb{Q}, the definition `BiLinearSymm.mk₂` constructs a symmetric bilinear map on VV if ff satisfies linearity in its first argument and symmetry. Specifically, it requires: 1. Scalar multiplication in the first factor: f(aS,T)=af(S,T)f(a \cdot S, T) = a \cdot f(S, T) for all aQa \in \mathbb{Q} and S,TVS, T \in V. 2. Addition in the first factor: f(S1+S2,T)=f(S1,T)+f(S2,T)f(S_1 + S_2, T) = f(S_1, T) + f(S_2, T) for all S1,S2,TVS_1, S_2, T \in V. 3. Symmetry (swap): f(S,T)=f(T,S)f(S, T) = f(T, S) for all S,TVS, T \in V. The linearity in the second factor is automatically derived from these properties.

theorem

f(aS,T)=af(S,T)f(a \cdot S, T) = a \cdot f(S, T) for symmetric bilinear forms

#map_smul₁

Let VV be a vector space over the rational numbers Q\mathbb{Q}. For any symmetric bilinear form ff on VV, any scalar aQa \in \mathbb{Q}, and any vectors S,TVS, T \in V, it holds that f(aS,T)=af(S,T)f(a \cdot S, T) = a \cdot f(S, T).

theorem

f(S,T)=f(T,S)f(S, T) = f(T, S) for symmetric bilinear forms

#swap

Let VV be a vector space over the rational numbers Q\mathbb{Q}. For any symmetric bilinear form ff on VV and for any vectors S,TVS, T \in V, the identity f(S,T)=f(T,S)f(S, T) = f(T, S) holds.

theorem

f(S,aT)=af(S,T)f(S, a \cdot T) = a \cdot f(S, T) for symmetric bilinear forms

#map_smul₂

Let VV be a vector space over the rational numbers Q\mathbb{Q}. For any symmetric bilinear form ff on VV, any scalar aQa \in \mathbb{Q}, and any vectors S,TVS, T \in V, the identity f(S,aT)=af(S,T)f(S, a \cdot T) = a \cdot f(S, T) holds.

theorem

f(S1+S2,T)=f(S1,T)+f(S2,T)f(S_1 + S_2, T) = f(S_1, T) + f(S_2, T) for symmetric bilinear forms

#map_add₁

Let VV be a vector space over the rational numbers Q\mathbb{Q}. For any symmetric bilinear form ff on VV and any vectors S1,S2,TVS_1, S_2, T \in V, the identity f(S1+S2,T)=f(S1,T)+f(S2,T)f(S_1 + S_2, T) = f(S_1, T) + f(S_2, T) holds.

theorem

f(S,T1+T2)=f(S,T1)+f(S,T2)f(S, T_1 + T_2) = f(S, T_1) + f(S, T_2) for symmetric bilinear forms

#map_add₂

Let VV be a vector space over the rational numbers Q\mathbb{Q}. For any symmetric bilinear form ff on VV and any vectors S,T1,T2VS, T_1, T_2 \in V, the identity f(S,T1+T2)=f(S,T1)+f(S,T2)f(S, T_1 + T_2) = f(S, T_1) + f(S, T_2) holds.

definition

The linear functional f(,T)f(\cdot, T) derived from a symmetric bilinear form ff

#toLinear₁

Let VV be a vector space over the rational numbers Q\mathbb{Q}. For a symmetric bilinear form ff on VV and a fixed vector TVT \in V, this definition represents the linear functional VQV \to \mathbb{Q} mapping Sf(S,T)S \mapsto f(S, T).

theorem

f(S,T)=f.toLinear1(T)(S)f(S, T) = f.\text{toLinear}_1(T)(S)

#toLinear₁_apply

Let VV be a vector space over the rational numbers Q\mathbb{Q}. For any symmetric bilinear form ff on VV and any vectors S,TVS, T \in V, the value of the form f(S,T)f(S, T) is equal to the evaluation of the linear functional f.toLinear1(T)f.\text{toLinear}_1(T) at the vector SS, where f.toLinear1(T)f.\text{toLinear}_1(T) denotes the linear map VQV \to \mathbb{Q} derived by fixing the second argument of ff as TT.

theorem

f(Si,T)=f(Si,T)f(\sum S_i, T) = \sum f(S_i, T) for Symmetric Bilinear Forms

#map_sum₁

Let VV be a vector space over the rational numbers Q\mathbb{Q} and let ff be a symmetric bilinear form on VV. For any natural number nn, any vector TVT \in V, and any family of vectors SiVS_i \in V indexed by i{0,,n1}i \in \{0, \dots, n-1\}, the following equality holds: f(i=0n1Si,T)=i=0n1f(Si,T)f\left(\sum_{i=0}^{n-1} S_i, T\right) = \sum_{i=0}^{n-1} f(S_i, T) where the left-hand side is the bilinear form applied to the sum of the vectors SiS_i and the vector TT, and the right-hand side is the sum of the values of the form applied to each individual SiS_i and TT.

theorem

f(T,Si)=f(T,Si)f(T, \sum S_i) = \sum f(T, S_i) for Symmetric Bilinear Forms

#map_sum₂

Let VV be a vector space (typically over Q\mathbb{Q} in this context) and let ff be a symmetric bilinear form on VV. For any natural number nn, any vector TVT \in V, and any family of vectors SiVS_i \in V indexed by i{0,,n1}i \in \{0, \dots, n-1\}, the following equality holds: f(T,i=0n1Si)=i=0n1f(T,Si)f(T, \sum_{i=0}^{n-1} S_i) = \sum_{i=0}^{n-1} f(T, S_i) where the left-hand side is the bilinear form applied to TT and the sum of the vectors SiS_i, and the right-hand side is the sum of the results of applying the form to TT and each individual SiS_i.

definition

Homogeneous quadratic map vτ(v,v)v \mapsto \tau(v, v) from symmetric bilinear form τ\tau

#toHomogeneousQuad

Let VV be a vector space over the field of rational numbers Q\mathbb{Q}. Given a symmetric bilinear form τ\tau on VV, this definition constructs a homogeneous quadratic map f:VQf: V \to \mathbb{Q} defined by f(v)=τ(v,v)f(v) = \tau(v, v) for every vector vVv \in V.

theorem

Q(S+T)=Q(S)+Q(T)+2τ(S,T)Q(S + T) = Q(S) + Q(T) + 2\tau(S, T) for the quadratic form QQ associated with symmetric bilinear form τ\tau

#toHomogeneousQuad_add

Let VV be a vector space over the rational numbers Q\mathbb{Q} and let τ\tau be a symmetric bilinear form on VV. Let Q:VQQ: V \to \mathbb{Q} be the associated homogeneous quadratic map defined by Q(v)=τ(v,v)Q(v) = \tau(v, v). For any vectors S,TVS, T \in V, the following identity holds: Q(S+T)=Q(S)+Q(T)+2τ(S,T)Q(S + T) = Q(S) + Q(T) + 2\tau(S, T)

definition

Homogeneous cubic map VQV \to \mathbb{Q}

#HomogeneousCubic

Let VV be a module over the field of rational numbers Q\mathbb{Q}. A homogeneous cubic equation (or map) is a function f:VQf: V \to \mathbb{Q} such that for any scalar aQa \in \mathbb{Q} and any element vVv \in V, the condition f(av)=a3f(v)f(a \cdot v) = a^3 f(v) is satisfied.

instance

A homogeneous cubic map ff as a function VQV \to \mathbb{Q}

#instFun

Let VV be a module over the field of rational numbers Q\mathbb{Q}. A homogeneous cubic map ff (an element of the type `HomogeneousCubic V`) can be treated as a function f:VQf : V \to \mathbb{Q}. This allows an instance of a cubic equation to be applied directly to an element vVv \in V to obtain a value in Q\mathbb{Q}.

theorem

f(aS)=a3f(S)f(a \cdot S) = a^3 f(S) for a homogeneous cubic map ff

#map_smul

Let VV be a module over the field of rational numbers Q\mathbb{Q}. For any homogeneous cubic map f:VQf: V \to \mathbb{Q}, any scalar aQa \in \mathbb{Q}, and any element SVS \in V, the identity f(aS)=a3f(S)f(a \cdot S) = a^3 f(S) holds.

instance

A symmetric trilinear form ff as a function V(VQVQQ)V \to (V \to_{\mathbb{Q}} V \to_{\mathbb{Q}} \mathbb{Q})

#instFun

Let VV be a module over the field of rational numbers Q\mathbb{Q}. An element ff of the type `TriLinearSymm V`, representing symmetric trilinear forms on VV, can be treated as a function f:V(VQVQQ)f : V \to (V \to_{\mathbb{Q}} V \to_{\mathbb{Q}} \mathbb{Q}). This allows a symmetric trilinear form to be applied sequentially to elements of VV to obtain a linear map, and eventually a scalar in Q\mathbb{Q}, reflecting the curried representation of a trilinear map.

definition

Symmetric trilinear map from first-factor linearity, f(S,T,L)=f(T,S,L)f(S, T, L) = f(T, S, L), and f(S,T,L)=f(S,L,T)f(S, T, L) = f(S, L, T)

#mk₃

Let VV be a vector space (or module) over the field of rational numbers Q\mathbb{Q}. Given a function f:V×V×VQf : V \times V \times V \to \mathbb{Q}, the constructor `TriLinearSymm.mk₃` defines a symmetric trilinear form on VV provided that ff satisfies linearity in its first argument and two specific swap symmetries. Specifically, it requires: 1. **Linearity in the first factor**: * Scalar multiplication: f(aS,T,L)=af(S,T,L)f(a \cdot S, T, L) = a \cdot f(S, T, L) for all aQa \in \mathbb{Q} and S,T,LVS, T, L \in V. * Addition: f(S1+S2,T,L)=f(S1,T,L)+f(S2,T,L)f(S_1 + S_2, T, L) = f(S_1, T, L) + f(S_2, T, L) for all S1,S2,T,LVS_1, S_2, T, L \in V. 2. **Symmetry between the first and second factors**: f(S,T,L)=f(T,S,L)f(S, T, L) = f(T, S, L) for all S,T,LVS, T, L \in V. 3. **Symmetry between the second and third factors**: f(S,T,L)=f(S,L,T)f(S, T, L) = f(S, L, T) for all S,T,LVS, T, L \in V. Because the map is symmetric, linearity in the second and third arguments is automatically satisfied by the linearity in the first.

theorem

f(S,T,L)=f(T,S,L)f(S, T, L) = f(T, S, L) for symmetric trilinear forms

#swap₁

Let VV be a module over the field of rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV and any vectors S,T,LVS, T, L \in V, the result of the form is invariant under the swapping of the first and second arguments, such that f(S,T,L)=f(T,S,L)f(S, T, L) = f(T, S, L).

theorem

f(S,T,L)=f(S,L,T)f(S, T, L) = f(S, L, T) for symmetric trilinear forms

#swap₂

Let VV be a module over the field of rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV and any vectors S,T,LVS, T, L \in V, the result of the form is invariant under the swapping of the second and third arguments, such that f(S,T,L)=f(S,L,T)f(S, T, L) = f(S, L, T).

theorem

f(S,T,L)=f(L,T,S)f(S, T, L) = f(L, T, S) for symmetric trilinear forms

#swap₃

Let VV be a module over the field of rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV and any vectors S,T,LVS, T, L \in V, the form is invariant under the swapping of the first and third arguments, such that f(S,T,L)=f(L,T,S)f(S, T, L) = f(L, T, S).

theorem

f(aS,T,L)=af(S,T,L)f(a \cdot S, T, L) = a f(S, T, L) for symmetric trilinear forms

#map_smul₁

Let VV be a module over the field of rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV, any scalar aQa \in \mathbb{Q}, and any vectors S,T,LVS, T, L \in V, the form satisfies the scalar homogeneity property in its first argument, such that f(aS,T,L)=af(S,T,L)f(a \cdot S, T, L) = a f(S, T, L).

theorem

f(S,aT,L)=af(S,T,L)f(S, a \cdot T, L) = a f(S, T, L) for symmetric trilinear forms

#map_smul₂

Let VV be a module over the field of rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV, any scalar aQa \in \mathbb{Q}, and any vectors S,T,LVS, T, L \in V, the form satisfies the scalar homogeneity property in its second argument: f(S,aT,L)=af(S,T,L).f(S, a \cdot T, L) = a f(S, T, L).

theorem

f(S,T,aL)=af(S,T,L)f(S, T, a \cdot L) = a f(S, T, L) for symmetric trilinear forms

#map_smul₃

Let VV be a module over the field of rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV, any scalar aQa \in \mathbb{Q}, and any vectors S,T,LVS, T, L \in V, the form satisfies the scalar homogeneity property in its third argument, such that: f(S,T,aL)=af(S,T,L).f(S, T, a \cdot L) = a f(S, T, L).

theorem

Additivity of Symmetric Trilinear Forms in the First Argument

#map_add₁

Let VV be a module over the field of rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV and any vectors S1,S2,T,LVS_1, S_2, T, L \in V, the form is additive in its first argument, such that f(S1+S2,T,L)=f(S1,T,L)+f(S2,T,L).f(S_1 + S_2, T, L) = f(S_1, T, L) + f(S_2, T, L).

theorem

Additivity of Symmetric Trilinear Forms in the Second Argument

#map_add₂

Let VV be a module over the field of rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV and any vectors S,T1,T2,LVS, T_1, T_2, L \in V, the form is additive in its second argument, such that f(S,T1+T2,L)=f(S,T1,L)+f(S,T2,L).f(S, T_1 + T_2, L) = f(S, T_1, L) + f(S, T_2, L).

theorem

Additivity of Symmetric Trilinear Forms in the Third Argument

#map_add₃

Let VV be a module over the field of rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV and any vectors S,T,L1,L2VS, T, L_1, L_2 \in V, the form is additive in its third argument, such that f(S,T,L1+L2)=f(S,T,L1)+f(S,T,L2).f(S, T, L_1 + L_2) = f(S, T, L_1) + f(S, T, L_2).

definition

Linear map Sf(S,T,L)S \mapsto f(S, T, L) from a symmetric trilinear form ff

#toLinear₁

Let VV be a vector space over the field of rational numbers Q\mathbb{Q}. Given a symmetric trilinear form ff on VV and two fixed vectors T,LVT, L \in V, the definition f.toLinear1(T,L)f.\text{toLinear}_1(T, L) is the linear map VQV \to \mathbb{Q} that sends a vector SVS \in V to the scalar value f(S,T,L)f(S, T, L). This is obtained by fixing the second and third arguments of the trilinear form.

theorem

f(S,T,L)=(f.toLinear1(T,L))(S)f(S, T, L) = (f.\text{toLinear}_1(T, L))(S)

#toLinear₁_apply

Let VV be a vector space over the field of rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV and any vectors S,T,LVS, T, L \in V, the value f(S,T,L)f(S, T, L) is equal to the value of the linear map f.toLinear1(T,L)f.\text{toLinear}_1(T, L) applied to SS. Here, f.toLinear1(T,L)f.\text{toLinear}_1(T, L) represents the linear map VQV \to \mathbb{Q} obtained by fixing TT and LL as the second and third arguments of the trilinear form.

theorem

f(Si,T,L)=f(Si,T,L)f(\sum S_i, T, L) = \sum f(S_i, T, L)

#map_sum₁

Let VV be a vector space (or module) over the field of rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV, any fixed vectors T,LVT, L \in V, and any finite collection of vectors SiVS_i \in V indexed by i{0,,n1}i \in \{0, \dots, n-1\}, the form satisfies linearity in its first argument: f(iSi,T,L)=if(Si,T,L)f\left(\sum_{i} S_i, T, L\right) = \sum_{i} f(S_i, T, L) Here, the application f(S,T,L)f(S, T, L) represents the evaluation of the trilinear form on the three vectors.

theorem

Linearity of symmetric trilinear forms in the second argument: f(T,Si,L)=f(T,Si,L)f(T, \sum S_i, L) = \sum f(T, S_i, L)

#map_sum₂

Let VV be a module over the field of rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV, any fixed vectors T,LVT, L \in V, and any finite collection of vectors SiVS_i \in V indexed by i{0,,n1}i \in \{0, \dots, n-1\}, the form satisfies linearity in its second argument: f(T,iSi,L)=if(T,Si,L)f\left(T, \sum_{i} S_i, L\right) = \sum_{i} f(T, S_i, L) Here, the application f(T,S,L)f(T, S, L) represents the evaluation of the trilinear form on the three vectors.

theorem

Linearity of symmetric trilinear forms in the third argument: f(T,L,Si)=f(T,L,Si)f(T, L, \sum S_i) = \sum f(T, L, S_i)

#map_sum₃

Let VV be a module over the rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV, and for any vectors T,LVT, L \in V and a finite collection of vectors SiVS_i \in V indexed by i{0,,n1}i \in \{0, \dots, n-1\}, the form satisfies linearity in its third argument: f(T,L,iSi)=if(T,L,Si)f(T, L, \sum_{i} S_i) = \sum_{i} f(T, L, S_i) Here, the curried application f(T,L,S)f(T, L, S) represents the evaluation of the trilinear form on the three vectors.

theorem

f(Si,Tk,Ll)=iklf(Si,Tk,Ll)f(\sum S_i, \sum T_k, \sum L_l) = \sum_i \sum_k \sum_l f(S_i, T_k, L_l) for symmetric trilinear forms

#map_sum₁₂₃

Let VV be a module over the field of rational numbers Q\mathbb{Q}. For any symmetric trilinear form ff on VV and any finite collections of vectors {Si}i<n1\{S_i\}_{i < n_1}, {Tk}k<n2\{T_k\}_{k < n_2}, and {Ll}l<n3\{L_l\}_{l < n_3} in VV, the form satisfies multilinearity across all three arguments simultaneously: f(iSi,kTk,lLl)=iklf(Si,Tk,Ll)f\left(\sum_{i} S_i, \sum_{k} T_k, \sum_{l} L_l\right) = \sum_{i} \sum_{k} \sum_{l} f(S_i, T_k, L_l) where the application f(S,T,L)f(S, T, L) represents the evaluation of the trilinear form on the three vectors.

definition

Homogeneous cubic map f(S)=τ(S,S,S)f(S) = \tau(S, S, S) from a symmetric trilinear form τ\tau

#toCubic

Let VV be a module over the field of rational numbers Q\mathbb{Q}. Given a symmetric trilinear form τ\tau on VV, this definition constructs a homogeneous cubic map f:VQf: V \to \mathbb{Q} defined by evaluation on the diagonal: f(S)=τ(S,S,S)f(S) = \tau(S, S, S) for any SVS \in V. This map ff satisfies the homogeneity condition f(aS)=a3f(S)f(a \cdot S) = a^3 f(S) for all scalars aQa \in \mathbb{Q} and vectors SVS \in V.

theorem

f(S+T)=f(S)+f(T)+3τ(S,S,T)+3τ(T,T,S)f(S + T) = f(S) + f(T) + 3\tau(S, S, T) + 3\tau(T, T, S) for homogeneous cubic map ff

#toCubic_add

Let VV be a module over the field of rational numbers Q\mathbb{Q}. Let τ\tau be a symmetric trilinear form on VV, and let f:VQf: V \to \mathbb{Q} be the associated homogeneous cubic map defined by f(X)=τ(X,X,X)f(X) = \tau(X, X, X). For any elements S,TVS, T \in V, the following identity holds: f(S+T)=f(S)+f(T)+3τ(S,S,T)+3τ(T,T,S)f(S + T) = f(S) + f(T) + 3\tau(S, S, T) + 3\tau(T, T, S)