Plectis

Long paper

The Binary Totient Series

Erdős #249 By July 2026; revised 1 October 2026 Authorship, AI use and citation

Summary. The dyadic totient sections through level e≥1 have an explicit rational basis of size 2e+1. Truncating a scaled tail difference produces an integer whose residue certifies nonintegrality when its distances from both endpoints of the residue interval exceed an explicit error bound. The record develops the resulting finite denominator exclusions, equivalent residue criteria, and sufficient exponential-sum estimates. Rational comparison sequences identify the limitations of particular size, parity, rank, and finite-prefix arguments. The short paper supplies the all-base basis theorem; here each conditional result carries the arithmetic hypothesis still needed to apply it. Those hypotheses are not established in the form required to prove irrationality of S=∑ φ(n)2−n.

This paper covers a claim-bounded problem-specific reasoning surface for Erdős #249: selected checked premises, finite certificates, closed routes, surviving obligations, and their exact evidence bands.

It does not establish the validity of claims tagged Lean, which belongs to the cited kernel-checked source, or a solution to Erdős #249, which remains open.

In this paper

Verification and reproducibility

The links below identify formal declarations at the supplied source revisions. A checked conditional implication retains its hypothesis; the linked source alone does not establish that input for φ. The record gives the available Lean and Comparator status and does not report a new replay or independent review of the printed proofs.

Bases and relations.

reduction of sections with residue zero; reduction of even residues; independence; span equality; basis; independence; dimension; the exact finite-truncation rank; infinite-dimensionality directly; coordinate specification; injective residues; unique representation; level count; section-index count; index as two plus the odd-residue count; full index count; a nonzero evaluation determinant; an invertible minor for affine totient sections; power-multiplication identity; affine cross-gcd identity; nonzero reduction scalar; all-base residue step; canonical spanning; span equality; rank in every base from independence; all-base truncation rank from independence; independence in every integer base; the rank of the retained all-base family; the rank of all sections through a finite level.

Tail identities, residue tests and carries.

the finite-prefix and tail identity; definition; certificates for shifts 1 through 8; nonintegral tail differences at the checked shifts; the integer carry recurrence and its growth bound; residue recurrence; comparison of the two residue conditions; exact equivalence; a certificate in each sufficiently late pair of multipliers; pointwise equivalence; global equivalence; equivalence after setting depth equal to the shift; irrationality and arbitrarily large certificates; the carry-rank lower bound under rationality; carry rank at least 2e−1 from independent totient sections; modular periodicity and the rank lower bound for the same carry; forcing vanishing; geometric reduction; identity; sign; primes; prime powers; unboundedness; exact centre decomposition; explicit error bound; separation criterion; target equivalence; endpoint nonnegativity; foreign-channel identity; five-point loss bound; simultaneous finite family; finite horizon; vanishing block; nonzero block; centrality equivalence; equivalence of the two conditions; conditional irrationality theorem; finite complement bound; exact channel split; conditional target-miss theorem; the periodic theorem; ∑φ(n)/(2n−1)=2; rationality and integer carries with controlled growth; diagonal split; definition; definition of the scaled tail; the proposed cyclotomic residue condition; the checked equivalence; checked conditional support/period counterexample; the checked binary-layer theorem; certificates with depth equal to the period multiple.

Finite denominator exclusions.

exclusion; reduced-denominator form; first failure; the conditional implication; farey gap; the denominator bound at window 240; denominator exclusion from a finite interval; the earlier denominator bound at window 120; denominator exclusion for the coprimality probability; list; verification; certificates at every scale through 82.

Least common multiples and limits of the tested methods.

certificate completeness; tail-difference integrality; irrationality iff every tail difference is nonintegral; exact frontier; forward implication; positive tail differences; negative endpoint representative; residue near the upper endpoint; divisibility preserved by finite combinations of shifts; the counterexample with sparse prescribed values; pointwise; cofinal at each shift; lcm diagonal; the certificate at t=24 and depth 23; the certificate at t=26 and depth 93; actual-orbit non-integrality at both heights; certificates beyond every threshold a0≤6; an explicit approximation error; the approximation as an integer over 4q; distance at least 1/32 from every integer; the cofinal separation hypothesis; the conditional endpoint theorem; the staircase is impossible under the stated room hypothesis; terminal-remainder identity; the limitation of fixed-precision valuation data; rationality from an integral tail difference.

Möbius identities and rational approximation.

unique minimizer; uniform lower bound 21/320; lower bound 1/16; 1/15 failure; positive weighted averages of the quotients; rational linear-form obstruction; divisor-count layer; first gcd moment; no fixed index; the primorial divisibility; irrationality of the Erdős–Borwein series; ∑μ(n)/(2n−1)=1/2; the squared-Mersenne expression for the totient series; the coprimality-probability expression; the Lambert-weighted sum over coprime positive pairs; the Stern–Brocot recursion with stopping; s=1; s=2; first difference; second difference.

Proposed exponential-sum and prime-factor estimates.

window-separated pairs; the unproved quantitative separation condition at primes; a positive adaptive truncation budget; S is irrational; density hypothesis; block-gap hypothesis; density-to-gap implication; exact squaring recurrence; iterate formula; initial-phase normal form; initial-phase equivalence; dyadic-root obstruction; prime-alignment implication; mixed difference; separable case; fixed-stencil uniqueness; a four-point divisor-layer identity; a centred representative for a residue class modulo an even modulus; eventual nontriviality and coprimality of the layers; order divisibility with bounded extension degree; exclusion of any fixed finite prime support; unbounded prime divisors; membership; injectivity; image equality; checked counterexample; the exact decomposition into four prime-factor contributions; the conditional irrationality theorem; the four inequalities on a common block; the first-harmonic bound from those four inequalities.

About this paper

Authorship and AI use. Will Cook built and directed the research infrastructure and maintains the public release. He reviewed claims when he could. AI agents did most of the research and drafting. Cook did not independently verify every claim.

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