Alphabeta Math
ExampleConstruction: AI-generatedVerification: AI-generatedprecheck passjudge pass (gpt-6.1-sol)
How statement and proof provenance work

The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.

  • Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
  • AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
  • AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.

These labels describe origin, not correctness: citations and verification chips remain separate evidence.

Worked affine transition between two inertial charts

Example

Worked computation of the transition between two inertial charts. Let (A,V,η,C+) be an oriented time-oriented affine Minkowski space with inertial frames (o;e0,e1,e2,e3) and (o′;e0′,e1′,e2′,e3′) and charts x(p)=E−1(p−o), x′(p)=E′−1(p−o′), and write ea′=∑bMabeb with M the change-of-basis matrix. Then for every event p,

x′(p)=M−1(x(p)−x(o′))=M−1x(p)+b,b:=−M−1x(o′),

so the transition is an affine map of R4 with invertible linear part M−1.

Restriction to the plane of e0,e1. Fix an inertial frame (o;e0,e1,e2,e3) with o the origin of A used in the charts, and a real parameter r, and put

e0′:=cosh⁡r e0+sinh⁡r e1,e1′:=sinh⁡r e0+cosh⁡r e1,e2′:=e2,e3′:=e3,

with o′:=o. Then (o′;e0′,e1′,e2′,e3′) is again an inertial frame: the matrix of the change of basis is the block matrix M=diag⁡((cosh⁡rsinh⁡rsinh⁡rcosh⁡r),I2) with det⁡M=cosh⁡2r−sinh⁡2r=1, and

M−1=diag⁡((cosh⁡r−sinh⁡r−sinh⁡rcosh⁡r),I2).

Since M has determinant 1, the two bases are positively oriented together; the new timelike vector satisfies η(e0′,e0′)=−cosh⁡2r+sinh⁡2r=−1<0 with cosh⁡r>∣sinh⁡r∣, so it is future timelike; hence the primed tuple is an inertial frame. The transition values are x′(o)=0 and x′(x−1(1,0,0,0))=(cosh⁡r,−sinh⁡r,0,0). Inertial frames exist at every event by Existence of future-oriented inertial frames at every event, so the computation applies with any chosen origin.

Facts & Assumptions

Given: The inertial frames and charts of the Example, with ea′=∑bMabeb, and the restricted basis with the hyperbolic parameter r.

[L1]

An inertial frame's ordered basis is η-orthonormal, future and positively oriented; its chart is x(p)=E−1(p−o), so x(o)=0; and for another inertial frame with chart x′ the transition law x′=M−1(x−x(o′)) holds (Inertial frames and inertial charts of the affine Minkowski model).

[L2]

cosh⁡u=(eu+e−u)/2>0 and sinh⁡u=(eu−e−u)/2 (The six hyperbolic functions and their natural domains), and cosh⁡2u−sinh⁡2u=1 for every real u (Addition formulas, identities, parity, and derivatives of the hyperbolic functions).

[L3]

In an η-orthonormal basis the matrix of η is diag⁡(−1,1,1,1), so η(v,w)=−v0w0+v1w1+v2w2+v3w3 (Inertial frames and inertial charts of the affine Minkowski model).

[L5]

The change-of-basis map between two ordered bases has det⁡>0 exactly when the bases lie in the same positive class; a positive class is an orientation and a basis in it is positively oriented (Orientation of a finite-dimensional real vector space).

[L6]

The change-of-basis matrix between two ordered bases is invertible (Invertible linear maps, linear isomorphisms, and inverse linear maps), and an expression u↦M−1u+b is an affine map of R4 (Affine spaces over a real vector space and displacement vectors).

Verification

technique · direct computation with the transition law and the hyperbolic identity
1.1L1L6algebra

For a general pair of inertial frames, substituting E′(u)=E(Mu), equivalently E′=E∘M, into x′=E′−1(p−o′) and using p−o′=E(x(p)−x(o′)) gives x′(p)=M−1(x(p)−x(o′))=M−1x(p)−M−1x(o′), an affine map with invertible linear part M−1 by [L1] and [L6].

1.2L1L2L3algebra

For the restricted basis, η(e0′,e0′)=−cosh⁡2r+sinh⁡2r=−1 and η(e1′,e1′)=−sinh⁡2r+cosh⁡2r=1 by [L3] and [L2], while η(e0′,e1′)=−cosh⁡rsinh⁡r+sinh⁡rcosh⁡r=0; also η(ei′,ej′)=δij for i,j∈{2,3} and the mixed entries vanish. Hence (e0′,e1′,e2′,e3′) is η-orthonormal by [L1].

1.3L2algebra

The matrix M of the restricted change of basis is the displayed block matrix, and det⁡M=cosh⁡2r−sinh⁡2r=1 by [L2]; its inverse is the displayed block matrix, since multiplying the two blocks gives the identity using cosh⁡2r−sinh⁡2r=1.

2.1step 1.2step 1.3L1L2L4L5algebra

By cosh⁡2r−sinh⁡2r=1 and cosh⁡r>0 one has cosh⁡r=1+sinh⁡2r>∣sinh⁡r∣ for every real r; with η(e0′,e0′)=−1<0 from step 1.2, the vector e0′ is future timelike by [L4]. Since det⁡M=1>0 by step 1.3, the primed basis lies in the same positive class as the positively oriented original basis by [L5]; hence (o′;e0′,e1′,e2′,e3′) is an inertial frame by [L1].

3.1step 1.1step 1.3L1L2algebra∎

With o′=o and x(o)=0 by [L1], the transition law of step 1.1 gives x′(o)=M−1(x(o)−x(o′))=0, and for the event p=x−1(1,0,0,0), whose coordinates in the first chart are x(p)=(1,0,0,0), it gives x′(p)=M−1(1,0,0,0)=(cosh⁡r,−sinh⁡r,0,0) by the inverse computed in step 1.3. This completes the worked computation of the transition and its two displayed values.

Depends on

Dependency tree · 2 levels

Sources