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Question 17998: Terms Tending to Zero Are Not a Sufficient Absolute-Convergence Criterion

On this page
  1. Original question and givens
  2. Definition and scope
  3. Step-by-step derivation
  4. Reverse checks
  5. Result
  6. This question review and source binding

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R0034-17998 · q-20261014-advance-20261104-r03-absolute-convergence-of-series-0098

Original question and givens

Use the shifted-harmonic boundary with positive shift=23 and inspected prefix_length=5. Give (shift, prefix_length, terms_tend_to_zero, term_zero_suffices_for_absolute_convergence, boundary).

  • G001 — Use the shifted-harmonic boundary with positive shift=23 and inspected prefix_length=5. Give (shift, prefix_length, terms_tend_to_zero, term_zero_suffices_for_absolute_convergence, boundary).

Definition and scope

Use the original question domain, assumptions and cited MKO definitions. This item has second-context mathematical and bilingual review, with the model, answer and every arithmetic step independently recomputed from the original parameters; the source question remains a candidate.

Step-by-step derivation

S001 · implies

Before

source operation=absseries-term-zero-boundary;original question snapshot retained;source presentation interface resolved in this page

After

EXPLICIT ordered output fields=[shift, prefix_length, terms_tend_to_zero, term_zero_suffices_for_absolute_convergence, boundary]

Conditions: none

Preserve the original snapshot's historical interface marker while listing the full ordered fields here,without browser JavaScript or an external lookup.Field labels are presentation metadata,not mathematical evaluation.The fourth term-zero No marks insufficiency,not a mislabeled second convergence flag.

Step identifiers and dependencies

Rule: absseries_explicit_source_interface_fields_without_javascript · Uses: G001

S002 · implies

Before

absolute-convergence term-zero counterexample:DECLARED whole positive tail b_k=1/(k+23),k>=0;shift>0

After

b_k decreases to0:for ANY epsilon>0 choose N with N+shift>1/epsilon,then every k>=N has b_k<epsilon

Conditions: none

Increasing denominators and an Archimedean cutoff supply the all-later bound for every epsilon,not an inference from the displayed prefix.

Step identifiers and dependencies

Rule: harmonic_full_tail_terms_zero_not_observed_prefix · Uses: G001, S001

S003 · implies

Before

absolute-convergence term-zero counterexample:same full absolute/positive series over denominators m=23,24,...

After

for every integer j>=0 large enough that2^j>=shift-1,the block m=2^j+1..2^(j+1) has2^j terms each>=1/2^(j+1);each block sum>=1/2;infinitely many disjoint blocks make partial sums unbounded

Conditions: none

Removing finitely many initial terms leaves the dyadic-block argument.Each sufficiently late block contributes at least1/2,so arbitrarily many disjoint blocks force unbounded partial sums.Terms tending to zero do not give a finite limit of partial sums.

Step identifiers and dependencies

Rule: harmonic_shifted_dyadic_blocks_diverge_not_term_limit · Uses: G001, S002

S004 · implies

Before

inspected finite prefix length=5;DECLARED harmonic tail shift=23;whole-tail term limit0 and divergent absolute sum proved separately

After

terms_tend_to_zero=Yes;term_zero_suffices_for_absolute_convergence=No;term_zero_not_absolute_convergence

Conditions: none

The fourth No answers whether the term-zero condition suffices,not a convergence test inferred from this prefix.The complete harmonic counterexample has terms tending to0 while its absolute series diverges.

Step identifiers and dependencies

Rule: absseries_term_zero_insufficiency_marker_not_prefix_classification · Uses: G001, S003

Reverse checks

  • S004 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S003 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S002 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S001 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.

Result

(23, 5, Yes, No, term_zero_not_absolute_convergence)

The full substitutions and premise checks give the original answer; source identity,format and status are unchanged.

This question review and source binding

Review date: 2026-10-26

Original questions, answers, step expressions, numeric ASTs and historical records are retained. Source candidate labels remain historical and are not overwritten as formal proof.

Source hashes and review receipts
  • input commit: 0f7be61e2c22317a4075561dc822c87d881a50db
  • original question SHA-256: 5c17801878a3a840d78d9e7fceb86547e530bb3840d7f4cbbbc5bc1f701df082
  • candidate record SHA-256: 68fea13ee915bc23a0dfb695ae126abd08e8d797c69df41f2f38e685519c92e7
  • semantic review receipt SHA-256: f73d099ebe3ff1c69a5d96f08c75b11b9e5b05120af40cf3ef388fce3b5c5336
  • question-first witness SHA-256: 22675ffb6209b4fea076032b29b96e3dc19aad4244c54493f5f65f5e5d875699
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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