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Question 34304: Counterexample to a Universal Proposition

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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R0067-34304 · q-20260921-proof-counterexample-universal-0004

Original question and givens

The domain is explicitly the integers. Consider the universal proposition “Every integer is a multiple of 3.” and the stated witness n=1. Does this witness refute that universal proposition?

  • G001 — The domain is explicitly the integers. Consider the universal proposition “Every integer is a multiple of 3.” and the stated witness n=1. Does this witness refute that universal proposition?

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 = [qf-proof-counterexample-universal, [bound, counterexample_role, domain, predicate_id, universal_statement, witness]]

After

derived = [BASE-no-required-operation, integers]

Conditions: none

Check THIS bank’s keys/operation/domain:legacy table underscores,MOD50 local hyphens;permissive BASE data acquires no unknown-field restriction.Keep Number.isInteger and SAFE source guards distinct,while preserving ORIGINAL JSON number representations.

Step identifiers and dependencies

Rule: R67_SOURCE_specific_keys_operation_domain_and_numeric_bank · Uses: G001

S002 · implies

Before

source roles = [multiple, 3, 1]

After

derived = [[1, 3, 1], No]

Conditions: none

FIRST match the stated predicate/bound and INTEGER domain.THEN substitute THIS integer witness and show failure.Use an exact nonzero remainder for even/multiple and retain strict/non-strict inequalities elsewhere.Do not use a metadata flag as an answer oracle.

Step identifiers and dependencies

Rule: Proof_UNIVERSAL_stated_predicate_and_INTEGER_witness_substitution · Uses: G001, S001

S003 · implies

Before

source roles = [multiple, 3, 1, No]

After

derived = [exists integer n with not predicate(n), not forall integers predicate(n), Yes]

Conditions: none

ONE actual counterexample IN the domain proves∃n ¬P(n),therefore refuting THIS∀n P(n).It does not prove every n fails,refute other propositions or make finite successful samples a universal proof.

Step identifiers and dependencies

Rule: Proof_ONE_actual_failure_refutes_ONLY_stated_forall · Uses: G001, S002

Reverse checks

  • S003 · premise_and_result_audit — Reverse-audit THIS step against the ORIGINAL roles,complete premises and field order.Distinguish implication from equivalence;preserve originals,English,MKOs,ASTs and review states.Finite checks are not independent review or general formal proof.
  • S002 · premise_and_result_audit — Reverse-audit THIS step against the ORIGINAL roles,complete premises and field order.Distinguish implication from equivalence;preserve originals,English,MKOs,ASTs and review states.Finite checks are not independent review or general formal proof.
  • S001 · premise_and_result_audit — Reverse-audit THIS step against the ORIGINAL roles,complete premises and field order.Distinguish implication from equivalence;preserve originals,English,MKOs,ASTs and review states.Finite checks are not independent review or general formal proof.

Result

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: fe7cf1a1b68c043cefc36eb7aae4fd49d773ceb9b667a464a52a0f27300da266
  • candidate record SHA-256: 94cfe11090fc431be33c1ada0a6d88f37baa33ade9c6d3c90aeeeb55176a18a3
  • semantic review receipt SHA-256: c89efa383b67bb2cf25bcf16160b9f5f614bbe5e5e791f4d7f58234d17a3371c
  • question-first witness SHA-256: 12766d451c5375842b4fc2843ae94807ec55f15763a916558026912a13873d57
  • Lean: NOT_RUN · human review: NOT_PERFORMED
Same-source full JSON