Plectis
Erdős problem #251

The prime-gap dyadic series

Is the dyadic series sum p_n/2^n over consecutive primes irrational? Equivalently, is the corresponding consecutive-prime-gap dyadic series irrational?

Open 1 Lean modules 2 main results Source directory

What is checked in Lean

  • The finite summation-by-parts identity relating the prime dyadic partial sums to the prime-gap dyadic partial sums, with an exact endpoint term and no convergence premise.
  • The factor-of-two normalisation between the two displayed indexings, at every finite horizon.
  • Conditional on summability of the prime dyadic series, the exact infinite prime-gap identity and the equivalence of irrationality of the prime and prime-gap series.
  • For an abstract integer-digit dyadic tail recurrence: the exact block identity, and that a shift of fixed length is integral exactly when an explicit scaled state is.
  • That one integral shift propagates to every later index.
  • That repeated doubling removes the power-of-two denominator, so every rational-valued dyadic recurrence has one fixed positive shift integral at all sufficiently late indices.
  • For a real-valued dyadic recurrence, cofinal non-integrality of every fixed positive shift implies irrationality of the initial state.
  • That the actual consecutive-prime-gap sequence is unbounded, by the factorial prime-free-interval construction, and therefore is not eventually periodic with any positive period.
  • For any integer-digit dyadic tail recurrence, two adjacent fixed-length shifts lying strictly between -1 and 1 cannot both be integral when the corresponding digits differ.
  • For the actual prime gaps, a cofinal supply of adjacent small-shift pairs with a mismatching gap excludes eventual integrality of that fixed shift.
  • The generic distance-to-integers core of the finite-truncation criterion: an approximation farther than its error bound from every integer certifies non-integrality.

Main results

Statements and boundaries are copied from the corpus record. Registry status: not_registered; the claim registry does not carry these declarations and kernel checking them does not promote them into reviewed public claims

What is not checked

  • The target irrationality.
  • The definition and recurrence of the concrete prime-gap tail as Lean infinite sums; the note supplies these at paper level. Summability of the concrete prime series is Lean-checked unconditionally via an elementary polynomial prime bound.
  • A theorem supplying cofinally many adjacent actual-prime-gap tail shifts in the open unit interval with the required gap mismatch.
  • Any theorem forcing periodicity or automaticity of the prime gaps from rationality; the free-carry identity disconfirms that route.

Open obligations

Prove any one of these and the corresponding reduction above becomes unconditional.

  • prime_gap_cofinal_shift_escape For every fixed h >= 1 and every N0, find N >= N0 for which sum_{j>=1} (g_{N+h+j}-g_{N+j})/2^j is not an integer.
  • cofinal_adjacent_small_mismatch For every fixed h >= 1 and every N0, find N >= N0 such that both adjacent full tail shifts have absolute value less than 1 and g_{N+h+1} != g_{N+1}. The checked local consumer then excludes eventual integrality of the h-shift.
  • actual_prime_gap_tail_formal_bridge Formalise summability of the actual prime and prime-gap dyadic series and identify the concrete infinite prime-gap tail with the checked real/rational dyadic recurrence, so the local consumer reaches the target series without a paper-only analytic bridge.

Lean modules

ModuleLinesDeclarationsTheorems
ErdosProblems.Erdos251.PrimeGapDyadicTail 1584 104 82

Comparator review

The Comparator replays selected exact interfaces against a pinned toolchain. It never widens what Lean proved.

Replayed by the Comparator

Statement and type parity replayed against the pinned toolchain.

  • Exact finite summation by parts, the unconditional infinite prime-gap identity, and irrationality equivalence.

    The equivalence does not prove irrationality of either series.

    prime_gap_reformulation · targeted

  • Prime gaps are unbounded and non-eventually-periodic, while an explicit nonperiodic unbounded countermodel still has rational sum.

    Comparator checks the exact theorem, not the broader methodological interpretation.

    coefficient_only_no_go · targeted_unboundedness_theorem_only

Represented indirectly

Covered through a neighbouring selected interface, not replayed one-to-one.

  • Odd rational denominators give totient-length integral shifts, and integrality propagates through the recurrence.

    This describes rational states and supplies no contradiction for actual prime gaps.

    totient_shift_propagation · represented_by_integral_shift_family

Outside the Comparator selection

Stated in the corpus; not part of the replayed interface set.

  • Block identities and exact denominator criteria classify rationality through integral positive tail shifts.

    The concrete prime-gap producer remains missing.

    integral_shift_classification · not_selected_abstract_family_represented_in_manifest

  • Cofinal adjacent small mismatches would rule out eventual integral shifts for the prime-gap tail.

    The cofinal mismatch producer is unproved.

    small_mismatch_criterion · not_selected_open_producer_hypothesis

The paper

Problem note 18 pp

An Integral-Shift Criterion for Dyadic Tail Recurrences

For any sequence obeying the dyadic recurrence with integer digits, a shift of length h is an integer exactly when one explicit multiple of the term is, and integrality then propagates to every later index; over the reals the contrapositive is an irrationality criterion. Applied to the prime-gap series, and conditional on a summability input the prime number theorem supplies but which is not formalised here, this makes the remaining obligation exact: cofinal non-integrality for every fixed h. Exact order-lattice and factorial-diagonal theorems then show that adaptive affine shifts and every fixed affine cylinder collapse rather than produce that obligation. These are scoped no-go results, not an irrationality proof; Erdős #251 stays open.