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Question 27301: Every Legal Split of a^p b^p Is Defeated by Pumping Down

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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R0053-27301 · q-20261015-advance-20261118-r07-pumping-lemma-regular-languages-0051

Original question and givens

Use positive pumping length p=1 and adversary word a^p b^p. Give (p, adversary_word, all_legal_split_rows, split_count, triangular_count, every_split_defeated, pump_down_scope).

  • G001 — Use positive pumping length p=1 and adversary word a^p b^p. Give (p, adversary_word, all_legal_split_rows, split_count, triangular_count, every_split_defeated, pump_down_scope).

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 roles = [pump-anbn-all-splits]

After

derived = [[p, adversary_word, all_legal_split_rows, split_count, triangular_count, every_split_defeated, pump_down_scope]]

Conditions: none

List the complete source field order and mode-specific roles without JavaScript or answer-shape inference;No,undefined and infinity retain their distinct meanings.

Step identifiers and dependencies

Rule: source_ordered_fields_without_JS · Uses: G001

S002 · implies

Before

source roles = [1]

After

derived = [a^1b^1, 2, ALL x>=0,y>=1,x+y<=p]

Conditions: none

Under assumed regularity take its pumping length p and choose a^p b^p of length2p>=p.Any legal xy lies in the initial p a-symbols,so y consists of a symbols and is nonempty.Do not preselect a convenient split.

Step identifiers and dependencies

Rule: Pumping_adversary_word_and_ALL_legal_split_domain · Uses: G001, S001

S003 · calculation

Before

Pumping ORIGINAL remaining a after i0 split0,1 := sub(1, 1)

After

Pumping ORIGINAL remaining a after i0 split0,1 = 0

Conditions: none

Substitute original roles and established intermediates exactly;no approximation,slot substitution or internally consistent changed operand.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · implies

Before

source roles = [1, 0, 1]

After

derived = [0, 1, [0, 1, 0, a^0b^1, No], Yes]

Conditions: none

The third field p-x-y counts only remaining a symbols in z;full |z| adds all p b-symbols.Pumping i=0 deletes nonempty y,leaving p-y<p a symbols but p b symbols,so this legal split fails membership.

Step identifiers and dependencies

Rule: Pumping_EVERY_legal_split_i0_refutation_remainingA_NOT_fullZ · Uses: G001, S003

S005 · calculation

Before

Pumping ORIGINAL triangular numerator := mul(1, 2)

After

Pumping ORIGINAL triangular numerator = 2

Conditions: none

Substitute original roles and established intermediates exactly;no approximation,slot substitution or internally consistent changed operand.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · calculation

Before

Pumping ORIGINAL triangular all-splits count := div(2, 2)

After

Pumping ORIGINAL triangular all-splits count = 1

Conditions: none

Substitute original roles and established intermediates exactly;no approximation,slot substitution or internally consistent changed operand.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S005

S007 · implies

Before

source roles = [1, [[0, 1, 0, a^0b^1, No]]]

After

derived = [1, 1, Yes]

Conditions: none

For each x there are p-x choices of y,total p(p+1)/2,so every legal split is included.The general argument repeats for ANY proposed p,with i=0 defeating every split.A table at one fixed p alone is not the general proof.

Step identifiers and dependencies

Rule: Pumping_ALL_splits_and_GENERAL_every_proposed_p_contradiction · Uses: G001, S006

Reverse checks

  • S007 · premise_and_result_audit — Reverse-check the complete original data,step operands and premises;finite checks,conditional named-theorem use and general formal proof remain distinct.
  • S006 · premise_and_result_audit — Recompute Pumping ORIGINAL triangular all-splits count with exact rational arithmetic, not rounded decimals.
  • S005 · premise_and_result_audit — Recompute Pumping ORIGINAL triangular numerator with exact rational arithmetic, not rounded decimals.
  • S004 · premise_and_result_audit — Reverse-check the complete original data,step operands and premises;finite checks,conditional named-theorem use and general formal proof remain distinct.
  • S003 · premise_and_result_audit — Recompute Pumping ORIGINAL remaining a after i0 split0,1 with exact rational arithmetic, not rounded decimals.
  • S002 · premise_and_result_audit — Reverse-check the complete original data,step operands and premises;finite checks,conditional named-theorem use and general formal proof remain distinct.
  • S001 · premise_and_result_audit — Reverse-check the complete original data,step operands and premises;finite checks,conditional named-theorem use and general formal proof remain distinct.

Result

(1, a^1b^1, [[0, 1, 0, a^0b^1, No]], 1, 1, Yes, every_legal_split_is_defeated_by_i=0)

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: 08137bddb3e722d3accdf7346ad57d409634a295ef626515d77fa010a1cf916f
  • candidate record SHA-256: 8220a3ccf65149320a66372bd49de3bad25394b91f72d65736c1df56d81e694b
  • semantic review receipt SHA-256: 1b7a62514347b82518305d5feb4369a52d7d44c442a0f2b131e9eb3cd7b45f62
  • question-first witness SHA-256: 79dc2a1077081f3ea2a03f75e32778163bf05e814cdf4c29ed86e567295f9ee1
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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