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

Hypotheses of the conditional implications

Uniformity in a parameter does not remove a hypothesis. An implication can hold at every scale although the required arithmetic input is known at only finitely many scales, or at none. We examine that distinction for the displayed implications, without drawing conclusions about all arguments that use the same objects.

Implications concerning the totient series

Cancellation versus a certificate.

The first-harmonic implication converts the stated cosine bound on one block into a finite residue certificate (exists_certifiedKill_of_first_harmonic_gap). To prove irrationality, the bound must hold with the quantifiers in Section 3: for every shift and beyond every block threshold. A finite identity for the sum, or a computation at one block, does not establish this assertion.

Sign versus distance from an integer.

The positivity theorem for the LCM tail difference (actualLcmTailDiff_shift_pos) identifies the relevant endpoint under the stated size and modulus bounds. Nonintegrality follows only after excluding the corresponding residue interval (actualLcmTailDiff_notMem_int_of_topEdgeResidueGap). Likewise, the terminal-dominance condition is a sufficient hypothesis, not a construction of the required parameters (PowerTwoFlexibleActualTerminalDominanceSupply). Under integrality its inequality contradicts positivity of the terminal carry; the contradiction establishes sufficiency, not the inequality itself.

An error bound versus a separated approximation.

The finite-tail approximation has a uniform error radius (abs_actualLcmTailOrbit_sub_rawApprox_lt). The cited exact check supplies nonintegrality at the two exponents a=4,6 (actualLcmTailOrbit_four_and_six_notMem_int); it is not an assertion that no other exponent works. To obtain irrationality by this criterion, separation must occur at arbitrarily large LCM scales. In the nondivisor approximation of Section 6.6.8, the error bound is also proved when D≥2H. Its remaining requirement is finite rational separation, not an additional convergence hypothesis.

Denominator growth versus approximation quality.

The lower bound for the product of the upper-half Mersenne factors (upperHalfMersenneProduct_lower_bound) concerns a denominator expression. An irrationality argument needs a comparison with the error of the corresponding approximation. Growth of that denominator expression alone does not give either a successful residue test or a nonintegral totient tail.

A rank lower bound versus a contradiction.

The coefficient independence and hypothetical-carry rank bounds hold uniformly in the level (linearIndependent_canonicalTotientKernelFamily, not_irrational_totientSeries_implies_unbounded_carryRank_unconditional). A contradiction would require an upper bound for the actual carry that is strictly smaller than the lower bound at some level. The rational 5/4 comparison disproves the proposed generic upper bound. The separate integer boundary conditions in the cited adjugate calculation are inconsistent (false_of_compressedAdjointCertificate), but that calculation does not exclude matrix arguments with different boundary conditions.

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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