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.
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These labels describe origin, not correctness: citations and verification chips remain separate evidence.
The single-flip code at : a nonperiodic coded orbit converging to the fixed point at both ends
Example
Take and let be the code with
the single-flip code. Then is constant outside a finite set (indeed outside ), is not the constant code , and is not periodic: for every , because the unique coordinate at which equals is whereas equals only at . Consequently the coded point satisfies and for every , while
Facts & Assumptions
Given: The parameter , the single-flip code , the coding map and the phase map of The quadratic map has a compact coded invariant set conjugate to the two-sign shift, with chaos under , and the fixed point , , of Constant codes give the fixed points, and finite nonconstant word codes give homoclinic orbits converging to a fixed point at both ends.
Finite-word data (Constant codes give the fixed points, and finite nonconstant word codes give homoclinic orbits converging to a fixed point at both ends): a code that equals the constant code outside a finite set has coded orbit converging to at both ends, and for ; distinct codes give distinct points.
Conjugacy and injectivity (The quadratic map has a compact coded invariant set conjugate to the two-sign shift, with chaos under , Finite symbol windows determine the code: locality of the iterates, coding continuity and injectivity of ): for all and , and is injective; hence would force , and would force .
The constant code (Constant codes give the fixed points, and finite nonconstant word codes give homoclinic orbits converging to a fixed point at both ends, clause 1): with .
Signs (The square-root recurrence is a contraction of with a unique coded solution, clause 4, Square roots exist: a unique with ; the positives are , Absolute value in an ordered field): for every code and every ; in particular because and .
Verification
Nonperiodicity of the code: for , the coordinate of equals , while ; hence . Also because .
The point differs from the fixed point: by [L4], , so directly; alternatively this follows from the injectivity and in [L1], [L2].
No return to the initial point: if for some , then by [L2], so by injectivity, contradicting step 1.1.
Two-sided convergence: the code equals outside , so [L1] applies with and gives as . Together with steps 2.1 and 2.2 this exhibits as a nonperiodic homoclinic point of the fixed point .
Remarks
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The verification uses only the coding dictionary and the finite-word convergence; it does not compute the coordinates of , which have no closed form.
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The same argument applies to every nonconstant code that is constant outside a finite set: none of these coded orbits is periodic, and each converges to the corresponding fixed point in both time directions.
Depends on
The quadratic map has a compact coded invariant set conjugate to the two-sign shift, with chaos under
Constant codes give the fixed points, and finite nonconstant word codes give homoclinic orbits converging to a fixed point at both ends
Finite symbol windows determine the code: locality of the iterates, coding continuity and injectivity of
The square-root recurrence is a contraction of with a unique coded solution
The two-sign bilateral shift space, its coding map, and the ball of bounded bilateral real sequences
Topological mixing, dense periodic points, sensitive dependence, and the stated chaos list
Square roots exist: a unique with ; the positives are
Absolute value in an ordered field
Dependency tree · 2 levels
Sources
- G. Teschl, Ordinary Differential Equations and Dynamical Systems, AMS Graduate Studies in Mathematics 140 (author's preliminary online edition, complete PDF), Section 13.2, homoclinic orbits and their codes
- R. Devaney and Z. Nitecki, Shift automorphisms in the Hénon mapping, Communications in Mathematical Physics 67 (1979) 137-146, coding of invariant orbits by bi-infinite sequences