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Question 27356: A Complete Unary DFA Loop Gives an Invariant for Every Pump Count

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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R0053-27356 · q-20261015-advance-20261118-r07-pumping-lemma-regular-languages-0031

Original question and givens

Use the unary DFA for lengths divisible by modulus=6, with accepted word length=12. Give (modulus, accepted_unary_word_length, first_modulus_plus_one_states, repeated_state_positions_and_state, x_length, y_length, z_length, all_pump_counts_invariant, loop_qualified).

  • G001 — Use the unary DFA for lengths divisible by modulus=6, with accepted word length=12. Give (modulus, accepted_unary_word_length, first_modulus_plus_one_states, repeated_state_positions_and_state, x_length, y_length, z_length, all_pump_counts_invariant, loop_qualified).

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-dfa-loop-witness]

After

derived = [[modulus, accepted_unary_word_length, first_modulus_plus_one_states, repeated_state_positions_and_state, x_length, y_length, z_length, all_pump_counts_invariant, loop_qualified]]

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 · calculation

Before

Pumping ORIGINAL unary z length := sub(12, 6)

After

Pumping ORIGINAL unary z length = 6

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, S001

S003 · implies

Before

source roles = [6, 12]

After

derived = [[0, 1, 2, 3, 4, 5], [[0, 1], [1, 2], [2, 3], [3, 4], [4, 5], [5, 0]], [0, 1, 2, 3, 4, 5, 0], [0, 6, 0], 0, 6, 6]

Conditions: none

The DFA state is length mod m;every unary transition adds1 modulo m.The first m+1 states repeat0 at positions0,m.The ORIGINAL word length is divisible by m,so x empty,y length m and the remaining z form a legal accepted word.

Step identifiers and dependencies

Rule: Pumping_complete_unary_DFA_cycle_and_actual_accepted_length · Uses: G001, S002

S004 · implies

Before

source roles = [6, 12, 6]

After

derived = [EVERY integer i>=0: pumped length=i*modulus+z, z is divisible by modulus, state remains0 after each loop;accepted, Yes]

Conditions: none

For arbitrary i>=0,traverse the same complete loop i times and then z.Since z is also divisible by m,the final state remains0.Full transitions and this quantified invariant support EVERY i,not sampled pump counts.

Step identifiers and dependencies

Rule: Pumping_ALL_i_loop_invariant_NOT_finite_pump_tests · Uses: G001, S003

Reverse checks

  • 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 — Reverse-check the complete original data,step operands and premises;finite checks,conditional named-theorem use and general formal proof remain distinct.
  • S002 · premise_and_result_audit — Recompute Pumping ORIGINAL unary z length with exact rational arithmetic, not rounded decimals.
  • 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

(6, 12, [0, 1, 2, 3, 4, 5, 0], [0, 6, 0], 0, 6, 6, for_all_i_length=(i*modulus)+z_is_0_mod_modulus, Yes)

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: 8a14aff3864c1bc8294166763e0b9b27e73ef724f407d165dac033d0698e9b0a
  • candidate record SHA-256: bacf62bdf44f8d7b2bc4f2f4aba473b247142cb349ee82ef86fe89502ea2d1a5
  • semantic review receipt SHA-256: 1b7a62514347b82518305d5feb4369a52d7d44c442a0f2b131e9eb3cd7b45f62
  • question-first witness SHA-256: 79dc2a1077081f3ea2a03f75e32778163bf05e814cdf4c29ed86e567295f9ee1
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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