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Question 21042: A Strict Epsilon Tail Needs the First Passing Index, Including Equality Boundaries

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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← Question derivation index · Original question batch

R0041-21042 · q-20261014-advance-20261108-r02-monotone-sequence-convergence-theorem-0067

Original question and givens

Use the whole real sequence a_n=L−c/(n+shift) for every n≥0, with L=17/18, positive c=17 and positive integer shift=2. The denominator shift is distinct from the theorem's supremum/infimum bound. The entire symbolic family, not a displayed finite prefix, supplies monotonicity and the corresponding bound. Direction=increasing, positive epsilon=1/26. Give (direction, limit, epsilon, N, value_at_N, strict_tail_certificate, certificate).

  • G001 — Use the whole real sequence a_n=L−c/(n+shift) for every n≥0, with L=17/18, positive c=17 and positive integer shift=2. The denominator shift is distinct from the theorem's supremum/infimum bound. The entire symbolic family, not a displayed finite prefix, supplies monotonicity and the corresponding bound. Direction=increasing, positive epsilon=1/26. Give (direction, limit, epsilon, N, value_at_N, strict_tail_certificate, certificate).

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=monoseq-epsilon-witness;original snapshot and mathematics retained

After

explicit ordered source output fields=[direction, limit, epsilon, N, value_at_N, strict_tail_certificate, certificate]

Conditions: none

Retain the historical interface marker while listing ordered output fields without JavaScript.Fields and tags are not extra mathematical evidence;fixed No markers retain their claim scope.

Step identifiers and dependencies

Rule: source_ordered_interface_explicit_without_javascript · Uses: G001

S002 · implies

Before

ORIGINAL direction=increasing,L=17/18,c=17>0,shift=2>=1;WHOLE a_n=L+(-1)c/(n+shift) for ALL n>=0

After

for EVERY n>=0,a_(n+1)-a_n=(1)*(17)/((n+2)*(n+1+2));positive denominator;all a_n strictly below L=17/18

Conditions: none

Subtract adjacent symbolic terms using a common denominator.Positivity fixes the sign and gives upper bound L in the increasing case or lower bound L in the decreasing case.This holds for all n,allows negative L,and is not a three-term sample proof.

Step identifiers and dependencies

Rule: monoseq_whole_symbolic_monotonicity_and_matching_bound · Uses: G001, S001

S003 · implies

Before

WHOLE increasing law with ORIGINAL L=17/18,c=17,shift=2

After

for ANY epsilon>0 choose natural N with N+2>17/epsilon;ALL n>=N have |a_n-L|<epsilon;L is supremum but NOT attained because c/(n+shift)>0

Conditions: none

The Archimedean choice controls every later term.Any smaller upper bound or larger lower bound is broken by a term sufficiently close to L,so L is the sup/inf.In the general monotone theorem,sup−epsilon is not an upper bound,which supplies a term;monotonicity then traps the tail.The decreasing proof is dual.

Step identifiers and dependencies

Rule: monoseq_sup_inf_limit_proof_and_nonattainment · Uses: G001, S002

S004 · calculation

Before

monoseq c over epsilon := div(17, 1/26)

After

monoseq c over epsilon = 442

Conditions: none

Substitute the original roles and established intermediates exactly,retaining order,signs and quantified conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · calculation

Before

monoseq index multiple := mul(1, 441)

After

monoseq index multiple = 441

Conditions: none

Substitute the original roles and established intermediates exactly,retaining order,signs and quantified conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · calculation

Before

monoseq actual source index := sum(0, 441)

After

monoseq actual source index = 441

Conditions: none

Substitute the original roles and established intermediates exactly,retaining order,signs and quantified conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S005

S007 · calculation

Before

monoseq witness denominator := sum(441, 2)

After

monoseq witness denominator = 443

Conditions: none

Substitute the original roles and established intermediates exactly,retaining order,signs and quantified conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S006

S008 · calculation

Before

monoseq witness distance := div(17, 443)

After

monoseq witness distance = 17/443

Conditions: none

Substitute the original roles and established intermediates exactly,retaining order,signs and quantified conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S007

S009 · calculation

Before

monoseq predecessor distance := div(17, 442)

After

monoseq predecessor distance = 1/26

Conditions: none

Substitute the original roles and established intermediates exactly,retaining order,signs and quantified conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S008

S010 · implies

Before

monoseq:c=17,shift=2,epsilon=1/26;index(q)=1q+0;c/epsilon=442;floor=442

After

least nonnegative witness=441;actual source index=441;distance=17/443<epsilon;predecessor distance=1/26;no predecessor evaluated when witness0

Conditions: none

Strict distance<epsilon means the denominator exceeds c/epsilon,so its integer threshold is floor(c/epsilon)+1.Round the affine index upward and clamp only the witness to0.Check the predecessor only when positive;equality still fails.

Step identifiers and dependencies

Rule: tail_strict_least_index_not_equality_or_negative_predecessor · Uses: G001, S009

S011 · implies

Before

monoseq:positive c=17,epsilon=1/26,shift=2,stride=1,offset=0;least witness=441

After

for EVERY integer q>=441,denominator=1q+0+2>=witness denominator>0,so 0<distance<=(17/443)<epsilon

Conditions: none

This is an algebraic inequality for every later index,not convergence guessed from one evaluated term.Positive increasing denominators and a fixed positive numerator control the whole tail;the predecessor check proves minimality only.

Step identifiers and dependencies

Rule: tail_all_later_quantified_from_positive_denominator_growth · Uses: G001, S010

S012 · calculation

Before

monoseq at witness N denominator := sum(441, 2)

After

monoseq at witness N denominator = 443

Conditions: none

Substitute the original roles and established intermediates exactly,retaining order,signs and quantified conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S011

S013 · calculation

Before

monoseq at witness N unsigned tail := div(17, 443)

After

monoseq at witness N unsigned tail = 17/443

Conditions: none

Substitute the original roles and established intermediates exactly,retaining order,signs and quantified conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S012

S014 · calculation

Before

monoseq at witness N signed value := sub(17/18, 17/443)

After

monoseq at witness N signed value = 7225/7974

Conditions: none

Substitute the original roles and established intermediates exactly,retaining order,signs and quantified conditions.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S013

Reverse checks

  • S014 · premise_and_result_audit — Recompute monoseq at witness N signed value with exact rational arithmetic, not rounded decimals.
  • S013 · premise_and_result_audit — Recompute monoseq at witness N unsigned tail with exact rational arithmetic, not rounded decimals.
  • S012 · premise_and_result_audit — Recompute monoseq at witness N denominator with exact rational arithmetic, not rounded decimals.
  • S011 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S010 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S009 · premise_and_result_audit — Recompute monoseq predecessor distance with exact rational arithmetic, not rounded decimals.
  • S008 · premise_and_result_audit — Recompute monoseq witness distance with exact rational arithmetic, not rounded decimals.
  • S007 · premise_and_result_audit — Recompute monoseq witness denominator with exact rational arithmetic, not rounded decimals.
  • S006 · premise_and_result_audit — Recompute monoseq actual source index with exact rational arithmetic, not rounded decimals.
  • S005 · premise_and_result_audit — Recompute monoseq index multiple with exact rational arithmetic, not rounded decimals.
  • S004 · premise_and_result_audit — Recompute monoseq c over epsilon with exact rational arithmetic, not rounded decimals.
  • 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

(increasing, 17/18, 1/26, 441, 7225/7974, Yes, forall_n_ge_N_by_monotone_symbolic_tail)

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: 278cdafdd3ae33b1a1af87f9ab2cbd8a7ca2fb1150f5555fff6e1f49ee861d47
  • candidate record SHA-256: e0466a21a14335e9363cb65bd43df969798d847104c2e04d5970836101f22bf4
  • semantic review receipt SHA-256: 8f134403487694af4c70d2e00ec84bab542043ef4b3c54517c04f3c409c0262a
  • question-first witness SHA-256: ad772845088ed8e99f87f90d4264b05ea97be35775305a02011af5ee35f0f4ce
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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