Explore related knowledge and questions →

Question 12528: Look Up One Pair without Assuming a Product Law

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

Return to catalogue page 63

← Question derivation index · Original question batch

R0024-12528 · q-20261013-advance-20261026-r04-finite-joint-distribution-0078

Original question and givens

Use the complete list of distinct integer pairs=[[-10, -1], [-9, 0], [-8, 1], [-7, 4]] and their aligned exact masses=[1/8, 1/4, 1/8, 1/2] on one common finite probability space. Qualification requires every mass to be nonnegative and their exact sum to be 1; zero masses are allowed. Preserve pair-mass alignment. Marginals alone do not specify this joint law or imply independence. No continuous or infinite-support conclusion is claimed. Use exact reduced rational outputs with positive denominators; omit /1 for integers. The joint table must qualify first; requested pair=[-8, 1]. Give (pair,mass), using zero when the pair is unlisted.

  • G001 — Use the complete list of distinct integer pairs=[[-10, -1], [-9, 0], [-8, 1], [-7, 4]] and their aligned exact masses=[1/8, 1/4, 1/8, 1/2] on one common finite probability space. Qualification requires every mass to be nonnegative and their exact sum to be 1; zero masses are allowed. Preserve pair-mass alignment. Marginals alone do not specify this joint law or imply independence. No continuous or infinite-support conclusion is claimed. Use exact reduced rational outputs with positive denominators; omit /1 for integers. The joint table must qualify first; requested pair=[-8, 1]. Give (pair,mass), using zero when the pair is unlisted.

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 · calculation

Before

joint law exact total := sum(1/8, 1/4, 1/8, 1/2)

After

joint law exact total = 1

Conditions: none

Compute exactly from the original roles and complete established operands,without changing pairings,order or replacing guards by approximation.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001

S002 · implies

Before

original ordered support=[[-10, -1], [-9, 0], [-8, 1], [-7, 4]];raw aligned masses=[[1, 8], [1, 4], [1, 8], [1, 2]]

After

normalized aligned masses=[1/8, 1/4, 1/8, 1/2];nonnegative=Yes;total=1;qualified=Yes

Conditions: none

Keep the complete joint table's original pair-mass alignment with distinct support pairs.Zero masses are allowed.Check nonnegativity and exact unit total separately;do not substitute marginals or a uniform law.

Step identifiers and dependencies

Rule: whole_joint_table_not_marginal_substitution · Uses: G001, S001

S003 · calculation

Before

requested joint pair mass := sum(1/8)

After

requested joint pair mass = 1/8

Conditions: none

Compute exactly from the original roles and complete established operands,without changing pairings,order or replacing guards by approximation.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · implies

Before

requested pair=[-8, 1];matching original indices=[2]

After

joint mass=1/8

Conditions: none

Look up this pair's mass in the original joint law.An unlisted pair has mass0;do not replace it by a product of marginals.

Step identifiers and dependencies

Rule: joint_lookup_not_product_of_marginals · Uses: G001, S003

Reverse checks

  • S004 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S003 · premise_and_result_audit — Recompute requested joint pair mass with exact rational arithmetic, not rounded decimals.
  • 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 — Recompute joint law exact total with exact rational arithmetic, not rounded decimals.

Result

([-8, 1], 1/8)

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: 881f25624f1c47785289893f60c2b6fe2401dc4d18391ed49aac4f3aa0ae147b
  • candidate record SHA-256: 292cd6c25c292062afcf27159b22815d93e88a1187a0b272b3b21315a462632f
  • semantic review receipt SHA-256: 1c8f6c2c6c75852cb93c08235684ce9f32ebe86065c58c693a04257e772c2d35
  • question-first witness SHA-256: 05fd764b5f9f7fff6185003efe576d87632f6daf40606ac3839a7feafe4f80d8
  • Lean: NOT_RUN · human review: NOT_PERFORMED
Same-source full JSON