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Question 31454: Distinct Real Eigenvalues of a Diagonal Matrix

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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R0061-31454 · q-20261006-advance-20261007-r04-eigenvalue-0029

Original question and givens

Over R, the 2×2 matrix is diag(-9,4). Give its distinct real eigenvalues as an increasing set with each value once.

  • G001 — Over R, the 2×2 matrix is diag(-9,4). Give its distinct real eigenvalues as an increasing set with each value once.

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-eigenvalue-diagonal-set, diagonal_eigenvalues, domain, reals]

After

derived = [[distinct_numeric_sorted_set]]

Conditions: none

Check THIS source interface:distance uses ONLY its complete coordinate frame;other families use a domain.Discrete operations use local hyphens,legacy banks underscores.Retain family-specific ordered output types and original bilingual data/status.

Step identifiers and dependencies

Rule: R61_SOURCE_exact_keys_operation_domain_OR_frame_and_output_roles · Uses: G001

S002 · implies

Before

source roles = [-9, 4]

After

derived = [[-9, 4], {-9, 4}]

Conditions: none

For diag(a,d),the characteristic factors are(a−λ)(d−λ),so the roots are a,d.Return the DISTINCT numerically sorted set,deduplicating equal roots.Zero is not an empty set;this is not a multiplicity list.

Step identifiers and dependencies

Rule: Eigen_DIAGONAL_characteristic_factors_DISTINCT_numeric_set · Uses: G001, S001

Reverse checks

  • S002 · premise_and_result_audit — Reverse-check the ORIGINAL inputs,types and premises;the conclusion need not uniquely recover its premises.This source-bound candidate is not independent review or formal proof.
  • S001 · premise_and_result_audit — Reverse-check the ORIGINAL inputs,types and premises;the conclusion need not uniquely recover its premises.This source-bound candidate is not independent review or formal proof.

Result

{-9, 4}

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: f77d90fc2d3bd731e89d73db03d08e66c0c9b2acd18291b8595adf98fc913189
  • candidate record SHA-256: f0add73ff114df23de3528a07ba350c34b17af2d402a7d5afa3e0dad67aaabf4
  • semantic review receipt SHA-256: 5403317467ff7c6b74c18ae7211530d0156ebc67d63fc00a3e07b81a201d3d69
  • question-first witness SHA-256: c2b5022aa77f803cd3e1ba9ce162a707da0281aa5bb5289111a97de51fe8c495
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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