Reading

The geometry every window shares.

A window is a nested grid of cells refining toward a point, and what it reads at bounded lookahead is what is Lipschitz at cell scale in its own metric: reading f at lookahead c means the output cell at depth t is a function of the input cell at depth t + c. The positional pair holds the two ends of that story, and the first two deletions: the tower reads the trailing digits of a base, every finite place kept and the archimedean place deleted — the first deletion (Walls) — while floating point reads the leading digits — the second, the mirror deletion, keeping only the archimedean place. Their shared criterion and exchanged blind spots are on The dual pole. Two constructions sit beside the pair: the continued-fraction grid, which is not positional at all, and the Zeckendorf window, which counts by Fibonacci numbers instead of powers (Completions). A digit set larger than the base — digits {−a..a} with 2a + 1 > b — is redundant: its cells overlap instead of partitioning. Throughout, rad m is the product of m's distinct primes.

The reading lemma

The two-pole reading criterion (The dual pole) names a metric and a cell family and nothing else — so it generalizes past the positional pair. A window is a metric measure geometry (X, d, μ, {Ct}): a metric, a measure, and a nested cover sequence with mesh δt → 0 and Lebesgue numbers t. A reader of f at lookahead c maps each deep input cell — every cell past some level of the nest — into an output cell containing its image, refinement-compatibly: the chosen output cells nest as the input refines, so the output is one committed digit stream.

The reading lemma rule

If f is Lipschitz with constant L, it fits cell-to-cell at lookahead c once L·δt+c < t — per-level fitting, which is readability outright where cells nest. Necessity is coarse: a readable map need only be Lipschitz at cell scale — pointwise Lipschitz follows where the cells are metric balls, and the leading window has maps readable at lookahead 0 with unbounded pointwise ratio. Three cover shapes give three regimes — balls of an ultrametric (t = δt, fitting automatic, margin 0); a partition of a connected space (t = 0, the lemma silent — readability a per-map alignment question); an overlapping cover with t = ρδt (fitting bought at margin logb(1/ρ)). At overlapping covers a redundant cell's children keep the overlap only in its interior, so the committed stream departs from the per-level bound by at most one digit — both directions realized at scanned witnesses; the bound is exact where cells nest. And readability is metric, not topological: even-position digit extraction is uniformly continuous — readable only at a modulus that grows with depth — and readable at no bounded lookahead.

Scope. Rule at scanned scopes; the two-pole criterion's regimes are its positional instances.

verifier: explore_reading_geometry.py

The wall criterion rule

At partition covers the lemma is silent, and the permanent-wall half of the alignment question is answered by the cover's vertex set ∂ — the cell-boundary points, which stay cell endpoints at every deeper level. For f continuous and strictly monotone at an irrational input y, the emitted digit count grows without bound iff f(y) ∉ ∂. Off ∂ the image sits strictly inside a cell at every depth, and the shrinking image intervals fit those cells one after another; an image on a vertex instead straddles it forever — a vertex lies interior to every image interval, and its two sides agree only to the vertex's own depth — so emission freezes at a computable constant, where a rate stall only slows it. A map's permanent walls are exactly f−1(∂) ∖ ∂, its rationalizing set. Redundant covers dissolve every wall: with a positive Lebesgue number no uniformly continuous map walls, an image interval smaller than that number fitting inside some cell wherever it lands. Wall exposure is therefore the size of the vertex set, and the continued fraction's — all of Q — is the largest a rational-vertex grid can have (base b: Z[1/b] ⊂ Q). The cross-window witness: x² walls permanently at √(1/3) in the continued-fraction grid and reads on in base 10.

Scope. Rule at scanned scopes — the maps x² (walls at every scanned √r) and √x (wall-free: a rational square root forces a rational input); the cure realized at every scanned wall of x².

verifiers: explore_cf_nonlinear.py, explore_cf_redundant.py

The third deletion: the continued-fraction window

Precision t = the first t partial quotients; the cell of [a0; a1, …, at] is a Stern–Brocot interval; cells partition the irrationals at each depth and nest across depths. This is the first window here that is not positional, and what it deletes is the constant ruler — the per-digit scale both positional windows hold fixed: its cell mesh is not a function of digit depth but of the number being read. It carries two metrics: the ultrametric on quotient strings, where reading at lookahead c is verbatim Lipschitz, and the value metric, where integer Möbius maps have honest Lipschitz constants. Their exchange rate is the Gauss-map entropy π²/(6 ln 2) almost everywhere (Shannon–McMillan–Breiman), with real fluctuations — the all-1s chain (the golden ratio φ) runs at the floor 2 ln φ, the fattest cells. A positional window is exactly the zero-variance case, where the two metrics are one ruler — so bounded lookahead forks here into digit-delay (quotients consumed minus emitted) and scale-delay (log of precision consumed over emitted), and the two disagree for real. The window's own measure is the Gauss measure, and the Gauss–Kuzmin digit law is this window's mirror of Benford — the invariant measure read through the digit grid (both classical).

The unit gate rule

An integer Möbius map with det = ±1 reads continued-fraction streams at bounded digit-delay: every nonnegative-entry unimodular map is a positive word in three exact transducers — the Stern–Brocot factorization — and delays add over a fixed word. A map with det ≠ ±1 is not boundedly readable: every one owns a mismatched witness. The sharp witness is 2φ = [3; 4, 4, 4, …] with φ³ = 2 + √5 exactly, so emitting t quotients of 2φ consumes 3t quotients of φ — delay linear. Non-unimodularity does not stall every orbit — (2x, √2) reads at delay zero, since 2√2 keeps √2's rate — it guarantees witnesses exist. Necessity is proved at quadratic streams: readability transports through unimodular factors (Smith normal form), reducing the gate to the scalings xnx, where φ is a universal witness — a matched rate would force the multiplier automorph of to be a power of φ, which floor rigidity (the period trace is strictly increasing in every digit) reserves for the all-1s word alone, so 's stream would be φ's own — but the multiplier ring sits inside the lattice, and φZ + Z. Serret's theorem — equal CF tails ⇔ GL(2, Z)-equivalence — is the classical shadow: readable multiplication is, again, the window's native units.

Scope. Positive direction proved for maps factoring as nonnegative words, and at quadratic streams outright, with no word route needed; sign-crossing words at general streams unscanned. Necessity proved at quadratic streams from proved pieces (floor rigidity, rate forcing, Serret transport).

verifiers: explore_cf_window.py, explore_cf_conductor.py, explore_cf_flow.py

The conductor law rule

At a quadratic stream the rate is arithmetic. The tail's period-matrix eigenvalue η equals εi(y)ε the field's fundamental unit, i(y) the unit index of the multiplier order of the lattice Z + Zy — so the cell-scale rate is r(y) = 2 i(y) RK / (y) (RK the regulator, the period length), and a measured stall ratio is (iout/iin)·(in/out). The delay is an instrument: the stall slope of xnx measures the unit index of a conductor order. Where the classical index ceiling is not attained, the law follows the realized index and the deficit is the order's ring class number against the field's. And the law is map-blind: any monotone C¹ map with nonzero derivative is conductor-priced at quadratic orbits — the map enters only through which output orbit it selects.

Scope. Rule at 17 measured pairs including four predicted before measurement; the automorph identity η = εi exact at all 53 scanned pairs (the eigenvalue identity itself is classical); map-blindness proved at the flow layer's scope, measured within 1% at all six scanned nonlinear pairs.

verifiers: explore_cf_conductor.py, explore_cf_nonlinear.py, explore_cf_flow.py

The commitment bound and rate forcing rule

Every scanned window's digit process is the shift of an expanding map whose per-digit scale ln |T′| is the roof of a suspension flow, and the flow's entropy is exactly 1 (Rokhlin's and Abramov's formulas): entropy per digit equals scale per digit, a positional window being the constant-roof case. The continued fraction's suspension is the modular geodesic flow (Artin, Series), where a quadratic tail rides a closed geodesic of flow period 2 ln η = 2 i RK per tail period — the conductor rate is the per-orbit return-time mean (the roof identity: over one tail period the product of complete quotients equals η, verified exactly at 25 tails). On this flow the commitment deficit D(n) = scale(image interval) − scale(committed cell) obeys 0 ≤ D(n) ≤ 3 ln(A + 2) + O(1) for monotone C¹ maps at badly approximable non-vertex outputs (quotients ≤ A): every reader is scale-synced regardless of the map — the scale clock always syncs, only the digit clock forks. Rate forcing: at an eventually periodic tail with quadratic output, emission is (rin/routn + O(1) with the ratio rational — digit delay is bounded iff the rates match, else linear with the mismatch sign, both signs realized. At a wall the deficit grows linearly instead: measured slope at (x², √2) is 1.7627 = 2 ln(1 + √2) to four decimals — the cusp excursion that never returns.

Scope. Both proved at stated scope — the bound by scale accounting plus bad approximability, the forcing verified at ten pairs including two witnesses constructed to run ahead. The ergodic vocabulary (suspension, roof, Abramov's formula) is classical import; the reading layer on top is the content.

verifier: explore_cf_flow.py

The redundant cover and the ladder law rule

The window's native redundant cover adds to the Stern–Brocot cells the straddle chains: at a vertex v with Farey parents (l, r), the chain cell Sk(v) runs between the k-th mediants and contains v in its interior at every k. The alphabet is the exact-real-arithmetic classic — the root straddle is the image (1/2, 2) of the modified Stern–Brocot digit M (Niqui's {L, R, M} digit set), and productivity for Möbius maps is classical (Gosper, Vuillemin, Edalat–Potts); what the overlap does and cannot do is the content. The ladder law: the cover cells containing a point z are z's own cell ladder plus a chain segment of exactly K(v, z) = ⌊1/(qv²|zv|) − qfar/qv⌋ rungs at each approached vertex — at a convergent, K equals the next partial quotient verbatim; at a rational the chain is infinite. The cover is graded: rank steps by +1 along every child relation, so overlap adds routes, never length. The two gates then split. The wall gate falls: x² reads √2, √3, √(3/2) through the chain with never-freezing emission, ln k slope equal to the input's scale rate to four decimals — the emitted stream is an infinite redundant representation of the rational output, the continued-fraction mirror of 0.1999… The rate gate stands: at the scanned pair (x/2, 2φ) — the staller of the tree clock, delay counted in Stern–Brocot tree steps rather than in quotients, its emission slope 3/4 — the maximal rank of a cover cell containing the image equals the plain tree position at every sampled depth — ladder spacing is orbit data no overlap changes, so rate forcing survives redundancy verbatim. And a delay's sign belongs to the clock: the inverse reading (2x, φ) of the same two streams stalls at 1/3 in the quotient clock and runs ahead at 4/3 in the tree clock, and (x/2, 2φ) does the reverse (φ³ = 2 + √5 makes all four slopes exact) — only the mismatch belongs to the orbit, and the scale clock is the invariant ruler.

Scope. The ladder law's closed form exact at every scanned node (510 nodes × 12 depths); the rank grading a property on every child relation; the wall cure and the rate gate rules at scanned scopes.

verifier: explore_cf_redundant.py

The two gates

The two gates across windows rule

Every window here gates its multiplication-like maps by the same shape: readable at bounded delay iff the map extends to a Lipschitz self-map of the window's completion. A window's completion is the limit object its nested cells define — the infinite digit strings, with the finite ones dense inside — and it is not the same object at every window (Completions). Every row of the table states that gate instead as unit-ness, and rightly: a window whose digit string carries a shift action has a native unit group, and there the two gates coincide. What the rows cannot show is which of the two is doing the work — the family below answers that, and the answer is not unit-ness.

windownative structuregated mapthe gate
trailing b-adicZ[1/b] x/vrad v | rad bv a unit
leading, non-redundantZ[1/b] on the scale circle ⌊(u/v)xrad u | rad bu a unit
continued fractionM2(Z) on quotient strings (ax + b)/(cx + d)det = ±1 — the map in GL(2, Z)
trailing ZeckendorfZ[φ] on digit strings nmn, n ↦ ⌊n/m m ∈ ±φZm a unit
trailing Ostrowski, α quadratic Z[α] on digit strings nmn, n ↦ ⌊n/m m ∈ ±εZm a unit

Nonlinear maps sit under a second gate, orthogonal to units — the wall criterion: x² reads φ at bounded delay (its input and output orbits share a rate) while walling permanently at √2 (its image is a vertex). Redundancy splits the gates by shape, and the split is verified at both redundant covers. The redundant leading window dissolves its gate wholesale, because positional roofs are constant — scale rates always match there, so the only gate was boundary alignment, which any positive Lebesgue number kills. The redundant continued-fraction cover dissolves only the wall gate — its roofs are orbit-pinned, so overlap extends terminated ladders (rationals: walls cured) while never raising the reachable rank at an irrational (rate forcing survives). One purchase — a positive Lebesgue number — two fates, decided by whether the window's roof is constant or carries orbit data.

Scope. The gate's iff is a theorem: delay c is exactly Lipschitz constant 2c in the agreement ultrametric on digit strings, and a Lipschitz map on a dense subset of a complete space extends uniquely — what it leaves between Lipschitz and discontinuous is the class the reading lemma's even-position extraction inhabits (Completions). Each row a rule at its own scopes; the gated half is a theorem at Zeckendorf (×2), and the last row's own theorem families are stated where they are proved (Quadratic windows). The redundancy split is a rule at the two covers scanned.

verifiers: explore_dual_lipschitz.py, explore_cf_window.py, explore_cf_redundant.py

Deletion is the price of locality: a window reads exactly what is continuous in the geometry its deletion leaves it, and every wall, gate and cure here — at the two ends of a numeration, and along the continued fraction's grid — is that statement's positive or negative space.

What the windows complete to

The gate's native form is an action on the limit object a window's nested cells define, and that object is not the same twice. Base b completes to a ring, so every integer multiplication is continuous there and only division is gated. The trailing Zeckendorf window — counting by Fibonacci numbers instead of by powers, its base ratio φ a unit of Z[φ] where an integer m ≥ 2 is not — completes to a space that is not a ring: ×2 has no continuous extension on it, a theorem with no range cap, and every other non-unit tested fails there too. The golden positional base completes to nothing new at all, its cells being singletons from the first cutoff up. Above those three stands a shape none of them describes, at every recurrence degree past the second, and past those a fifth where the image limit points stop being finitely many — and wherever it has been read, the arithmetic keeps clear of the class between Lipschitz and discontinuous — Completions.

The family above Zeckendorf

Zeckendorf is one window of a family with a member for every quadratic irrational — the trailing Ostrowski windows, which count by the convergent denominators of an irrational α's continued fraction as Zeckendorf counts by the Fibonacci numbers, φ's own — and across the quadratic windows tested the gate tracks the unit group of Z[α], so the whole family completes as Zeckendorf does, to an object that is not a ring. That tracking is a fact about these windows and not about the gate: a quadratic window's continued fraction is eventually periodic, which is exactly what gives it a unit for the gate to track. The not-a-ring half of that placement is proved by an explicit witness family at every constant-a and [0; 1, a] period-2 window and at period-3 [0; 1, 1, 2], and at every irrational window, for every multiplier, by a family built on two consecutive convergents whose images straddle a point the completion codes twice — the flip's address a theorem everywhere, with a certified boundary family and one 2-adic criterion on the multiplier deciding where the older witness runs beside it — Quadratic windows.

The second deletion

The positional pair carries one criterion with the poles swapped: a window reads a map at bounded lookahead iff the map is Lipschitz at cell scale in the window's own metric and each deep cell's image fits one output cell — the fitting clause priced by the cell family's Lebesgue number. The two poles exchange crown and blind spot — the tower's exact zero-test against floating point's native size, sign and order — and base b's trailing digits read exactly the primes p | b that its leading digits perfectly hide — The dual pole.