Plectis

Long paper

Reciprocal Mersenne Subseries

Summary. A weighted summability criterion proves irrationality of reciprocal Mersenne subseries: if h is the part of a supported on a finite nonempty prime set P, every infinite A with ∑ h(a)/(a(bh(a)−1)) finite has irrational ∑ (ba−1)−1. The base-two condition gives the conclusion at every integer base for every infinite subset, and permits an example with divergent reciprocal sum, while excluding full support and all odd exponents. The proof averages over a finite part of the support and over dyadic observation lengths. Erdős's weaker reciprocal-summable theorem is proved in full, and a common window extends both arguments to unions of weighted and positive-cover supports. Finite-denominator and achievement-set calculations formulate tests for the targets 1/2 and 1/21; those tests do not decide either target or the universal question. Prime support at base 2 and squarefree support at power-of-two bases are attributed as existing work.

This paper covers a claim-bounded problem-specific reasoning surface for Erdős #257: selected checked premises, finite computations, 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 #257, whose universal and half-value questions remain open.

In this paper
One-step quotient identities

Theorem 6.89 (The next floor quotient). For d≥2 and M≥0, the floor quotient satisfies

q(M+1,d)=2q(M,d)+1d∣M+1.

Indeed, q(M,d)=∑j=1⌊M/d⌋2M−jd. Increasing M doubles each existing term and adds 1 exactly when M+1 is divisible by d. Thus a quotient doubles or doubles plus one; it does not remain unchanged except when both values are zero. Summing over a fixed finite support gives the corresponding update with added term cD(M+1).

Theorem 6.90 (The next quotient sum). For a fixed finite set D⊆{2,3,…} and M≥0,

Q(D,M+1)=2Q(D,M)+cD(M+1).

This is the sum of Theorem 6.89 over d∈D. Keeping D fixed is essential: changing the support between steps adds a separate difference of quotient sums. The exclusion of d=1 is also essential for the displayed correction term, since q(M,1)=2M doubles without an added unit.

Theorem 6.91 (The signed endpoint recurrence). The signed next-step expression is H(D,k,n)=2S(D,k,n−1)+1−cD(n). The last term counts the selected exponents dividing the new endpoint. This is the same recurrence shape as the generic tempered-orbit recurrence u(N+1)=2u(N)−v⋅c(N+1) from the tempered-orbit criterion (Theorem 6.105 below), specialised to Mersenne local repair. A matching recurrence alone does not imply rationality: Theorem 6.105 also requires one fixed coefficient sequence, integer states and a vanishing scaled limit. Those additional conditions must be checked before that criterion can be applied to these finite-row quantities.

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.

Cite and contact. Cite this paper by its title, author and date above, with its PDF; cite the earlier sources it uses for a mathematical result. For software, use the release citation and give the commit used. Contact Will with questions or corrections.

Prefer the manuscript?

Equations typeset from the exact TeX. Rendered from the LaTeX manuscript source with file fingerprint sha256:47cf6a152738f17c. Its file fingerprint matched the published source record, so the PDF above, the LaTeX, and this page are one manuscript. Redeploying the site regenerates this page from whatever the public repository holds at that moment.