Explore related knowledge and questions →

Question 14081: Keep Verified Independence and Zero Covariance Distinct

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 71

← Question derivation index · Original question batch

R0027-14081 · q-20261014-advance-20261028-r06-random-variable-independence-0081

Original question and givens

Use the complete joint grid with original x_values=[-7, 18], y_values=[2, 25], and aligned row-by-column exact masses=[[30/49, 12/49], [5/49, 2/49]]. Value labels must be distinct in each nonempty list, all masses nonnegative and their total exactly 1. Preserve grid order and zero masses; all marginals, events and moments use this same law. Two-variable independence requires factorization for every grid pair; it implies neither identical distribution, IID, Markov behavior nor larger-family mutual independence. Use exact reduced rational outputs with positive denominators; omit /1 for integers. Give (independent?,E_X,E_Y,E_XY,covariance,implication_pass,boundary=zero_covariance_converse_not_claimed). Despite the source field name, implication_pass is the conjunction of both verified independence and zero covariance in this protocol, not a truth value of material implication.

  • G001 — Use the complete joint grid with original x_values=[-7, 18], y_values=[2, 25], and aligned row-by-column exact masses=[[30/49, 12/49], [5/49, 2/49]]. Value labels must be distinct in each nonempty list, all masses nonnegative and their total exactly 1. Preserve grid order and zero masses; all marginals, events and moments use this same law. Two-variable independence requires factorization for every grid pair; it implies neither identical distribution, IID, Markov behavior nor larger-family mutual independence. Use exact reduced rational outputs with positive denominators; omit /1 for integers. Give (independent?,E_X,E_Y,E_XY,covariance,implication_pass,boundary=zero_covariance_converse_not_claimed). Despite the source field name, implication_pass is the conjunction of both verified independence and zero covariance in this protocol, not a truth value of material implication.

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 grid model whole mass sum := sum(30/49, 12/49, 5/49, 2/49)

After

joint grid model whole mass sum = 1

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001

S002 · implies

Before

joint grid model:raw aligned masses=[[30, 49], [12, 49], [5, 49], [2, 49]]

After

normalized masses=[30/49, 12/49, 5/49, 2/49];nonnegative=Yes;total=1

Conditions: none

First qualify nonnegativity and exact unit total on one complete finite probability model.Retain zero-mass atoms;do not assume uniformity or substitute another model.

Step identifiers and dependencies

Rule: whole_finite_probability_law_not_uniform_assumption · Uses: G001, S001

S003 · implies

Before

original x row labels=[-7, 18];original y column labels=[2, 25]

After

normalized aligned row-by-column joint grid=[[30/49, 12/49], [5/49, 2/49]]

Conditions: none

Each value list is distinct but need not be numerically sorted.Pair every mass with its original row/column,including zero cells;sorting values must not misalign the grid.

Step identifiers and dependencies

Rule: RV_joint_grid_original_order_not_value_sort · Uses: G001, S002

S004 · calculation

Before

X row0 marginal := sum(30/49, 12/49)

After

X row0 marginal = 6/7

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · calculation

Before

X row1 marginal := sum(5/49, 2/49)

After

X row1 marginal = 1/7

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · calculation

Before

Y column0 marginal := sum(30/49, 5/49)

After

Y column0 marginal = 5/7

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S005

S007 · calculation

Before

Y column1 marginal := sum(12/49, 2/49)

After

Y column1 marginal = 2/7

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S006

S008 · calculation

Before

joint cell row0 column0 marginal product := mul(6/7, 5/7)

After

joint cell row0 column0 marginal product = 30/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S007

S009 · implies

Before

original row=0;column=0;value labels=[-7, 2];joint mass=30/49;marginal product=30/49

After

cell factorizes=Yes

Conditions: none

Audit every cell's singleton-event product,including zeros.One failed cell gives a singleton-preimage counterexample.Retain original row-major failure order.

Step identifiers and dependencies

Rule: RV_independence_every_joint_cell · Uses: G001, S008

S010 · calculation

Before

joint cell row0 column1 marginal product := mul(6/7, 2/7)

After

joint cell row0 column1 marginal product = 12/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S009

S011 · implies

Before

original row=0;column=1;value labels=[-7, 25];joint mass=12/49;marginal product=12/49

After

cell factorizes=Yes

Conditions: none

Audit every cell's singleton-event product,including zeros.One failed cell gives a singleton-preimage counterexample.Retain original row-major failure order.

Step identifiers and dependencies

Rule: RV_independence_every_joint_cell · Uses: G001, S010

S012 · calculation

Before

joint cell row1 column0 marginal product := mul(1/7, 5/7)

After

joint cell row1 column0 marginal product = 5/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S011

S013 · implies

Before

original row=1;column=0;value labels=[18, 2];joint mass=5/49;marginal product=5/49

After

cell factorizes=Yes

Conditions: none

Audit every cell's singleton-event product,including zeros.One failed cell gives a singleton-preimage counterexample.Retain original row-major failure order.

Step identifiers and dependencies

Rule: RV_independence_every_joint_cell · Uses: G001, S012

S014 · calculation

Before

joint cell row1 column1 marginal product := mul(1/7, 2/7)

After

joint cell row1 column1 marginal product = 2/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S013

S015 · implies

Before

original row=1;column=1;value labels=[18, 25];joint mass=2/49;marginal product=2/49

After

cell factorizes=Yes

Conditions: none

Audit every cell's singleton-event product,including zeros.One failed cell gives a singleton-preimage counterexample.Retain original row-major failure order.

Step identifiers and dependencies

Rule: RV_independence_every_joint_cell · Uses: G001, S014

S016 · implies

Before

all joint factorization failures=[]

After

random variables independent=Yes;all-cell factorization covers every value-event rectangle

Conditions: none

If every cell factorizes,any value-event rectangle sum splits into a product of marginal sums,covering every preimage-event choice.This implies no identical distribution,IID,Markov behavior or larger-family mutual independence.

Step identifiers and dependencies

Rule: RV_all_cells_to_all_event_preimages · Uses: G001, S015

S017 · calculation

Before

moment row0 col0 weighted X := mul(30/49, -7)

After

moment row0 col0 weighted X = -30/7

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S016

S018 · calculation

Before

moment row0 col0 weighted Y := mul(30/49, 2)

After

moment row0 col0 weighted Y = 60/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S017

S019 · calculation

Before

moment row0 col0 XY := mul(-7, 2)

After

moment row0 col0 XY = -14

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S018

S020 · calculation

Before

moment row0 col0 weighted XY := mul(30/49, -14)

After

moment row0 col0 weighted XY = -60/7

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S019

S021 · calculation

Before

moment row0 col1 weighted X := mul(12/49, -7)

After

moment row0 col1 weighted X = -12/7

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S020

S022 · calculation

Before

moment row0 col1 weighted Y := mul(12/49, 25)

After

moment row0 col1 weighted Y = 300/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S021

S023 · calculation

Before

moment row0 col1 XY := mul(-7, 25)

After

moment row0 col1 XY = -175

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S022

S024 · calculation

Before

moment row0 col1 weighted XY := mul(12/49, -175)

After

moment row0 col1 weighted XY = -300/7

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S023

S025 · calculation

Before

moment row1 col0 weighted X := mul(5/49, 18)

After

moment row1 col0 weighted X = 90/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S024

S026 · calculation

Before

moment row1 col0 weighted Y := mul(5/49, 2)

After

moment row1 col0 weighted Y = 10/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S025

S027 · calculation

Before

moment row1 col0 XY := mul(18, 2)

After

moment row1 col0 XY = 36

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S026

S028 · calculation

Before

moment row1 col0 weighted XY := mul(5/49, 36)

After

moment row1 col0 weighted XY = 180/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S027

S029 · calculation

Before

moment row1 col1 weighted X := mul(2/49, 18)

After

moment row1 col1 weighted X = 36/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S028

S030 · calculation

Before

moment row1 col1 weighted Y := mul(2/49, 25)

After

moment row1 col1 weighted Y = 50/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S029

S031 · calculation

Before

moment row1 col1 XY := mul(18, 25)

After

moment row1 col1 XY = 450

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S030

S032 · calculation

Before

moment row1 col1 weighted XY := mul(2/49, 450)

After

moment row1 col1 weighted XY = 900/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S031

S033 · calculation

Before

grid E_X := sum(-30/7, -12/7, 90/49, 36/49)

After

grid E_X = -24/7

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S032

S034 · calculation

Before

grid E_Y := sum(60/49, 300/49, 10/49, 50/49)

After

grid E_Y = 60/7

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S033

S035 · calculation

Before

grid E_XY := sum(-60/7, -300/7, 180/49, 900/49)

After

grid E_XY = -1440/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S034

S036 · calculation

Before

grid product of means := mul(-24/7, 60/7)

After

grid product of means = -1440/49

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S035

S037 · calculation

Before

grid covariance := sub(-1440/49, -1440/49)

After

grid covariance = 0

Conditions: none

Compute exactly from original roles,complete pairings and established intermediates,retaining denominators,signs and zeros.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S036

S038 · implies

Before

verified independence=Yes;E_X=-24/7;E_Y=60/7;E_XY=-1440/49;covariance=0

After

source implication_pass is conjunction(independent,covariance0)=Yes,not material implication

Conditions: none

Verified all-cell independence distributes the finite double sum to E[XY]=E[X]E[Y],hence Cov=0.Despite the field name implication_pass,the protocol asks both facts to hold.A dependent zero-covariance model still returns No;this neither refutes the theorem nor proves the converse.

Step identifiers and dependencies

Rule: RV_zero_covariance_conjunction_not_converse · Uses: G001, S037

Reverse checks

  • S038 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S037 · premise_and_result_audit — Recompute grid covariance with exact rational arithmetic, not rounded decimals.
  • S036 · premise_and_result_audit — Recompute grid product of means with exact rational arithmetic, not rounded decimals.
  • S035 · premise_and_result_audit — Recompute grid E_XY with exact rational arithmetic, not rounded decimals.
  • S034 · premise_and_result_audit — Recompute grid E_Y with exact rational arithmetic, not rounded decimals.
  • S033 · premise_and_result_audit — Recompute grid E_X with exact rational arithmetic, not rounded decimals.
  • S032 · premise_and_result_audit — Recompute moment row1 col1 weighted XY with exact rational arithmetic, not rounded decimals.
  • S031 · premise_and_result_audit — Recompute moment row1 col1 XY with exact rational arithmetic, not rounded decimals.
  • S030 · premise_and_result_audit — Recompute moment row1 col1 weighted Y with exact rational arithmetic, not rounded decimals.
  • S029 · premise_and_result_audit — Recompute moment row1 col1 weighted X with exact rational arithmetic, not rounded decimals.
  • S028 · premise_and_result_audit — Recompute moment row1 col0 weighted XY with exact rational arithmetic, not rounded decimals.
  • S027 · premise_and_result_audit — Recompute moment row1 col0 XY with exact rational arithmetic, not rounded decimals.
  • S026 · premise_and_result_audit — Recompute moment row1 col0 weighted Y with exact rational arithmetic, not rounded decimals.
  • S025 · premise_and_result_audit — Recompute moment row1 col0 weighted X with exact rational arithmetic, not rounded decimals.
  • S024 · premise_and_result_audit — Recompute moment row0 col1 weighted XY with exact rational arithmetic, not rounded decimals.
  • S023 · premise_and_result_audit — Recompute moment row0 col1 XY with exact rational arithmetic, not rounded decimals.
  • S022 · premise_and_result_audit — Recompute moment row0 col1 weighted Y with exact rational arithmetic, not rounded decimals.
  • S021 · premise_and_result_audit — Recompute moment row0 col1 weighted X with exact rational arithmetic, not rounded decimals.
  • S020 · premise_and_result_audit — Recompute moment row0 col0 weighted XY with exact rational arithmetic, not rounded decimals.
  • S019 · premise_and_result_audit — Recompute moment row0 col0 XY with exact rational arithmetic, not rounded decimals.
  • S018 · premise_and_result_audit — Recompute moment row0 col0 weighted Y with exact rational arithmetic, not rounded decimals.
  • S017 · premise_and_result_audit — Recompute moment row0 col0 weighted X with exact rational arithmetic, not rounded decimals.
  • S016 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S015 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S014 · premise_and_result_audit — Recompute joint cell row1 column1 marginal product with exact rational arithmetic, not rounded decimals.
  • S013 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S012 · premise_and_result_audit — Recompute joint cell row1 column0 marginal product with exact rational arithmetic, not rounded decimals.
  • S011 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S010 · premise_and_result_audit — Recompute joint cell row0 column1 marginal product with exact rational arithmetic, not rounded decimals.
  • S009 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S008 · premise_and_result_audit — Recompute joint cell row0 column0 marginal product with exact rational arithmetic, not rounded decimals.
  • S007 · premise_and_result_audit — Recompute Y column1 marginal with exact rational arithmetic, not rounded decimals.
  • S006 · premise_and_result_audit — Recompute Y column0 marginal with exact rational arithmetic, not rounded decimals.
  • S005 · premise_and_result_audit — Recompute X row1 marginal with exact rational arithmetic, not rounded decimals.
  • S004 · premise_and_result_audit — Recompute X row0 marginal with exact rational arithmetic, not rounded decimals.
  • S003 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • 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 grid model whole mass sum with exact rational arithmetic, not rounded decimals.

Result

(Yes, -24/7, 60/7, -1440/49, 0, Yes, zero_covariance_converse_not_claimed)

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: 998b40bccc1837425ea031db99ee60d8636a193b0bd0cd8ddff156546d6666ef
  • candidate record SHA-256: 48665a41b0b9f4e9a9b2ec3092897b37e620a8be842b37c78c66a0d1226866c6
  • semantic review receipt SHA-256: e49bf5eaa968c09ebac4ad538ce58251671ed922c957cee1471cfc7b68934bfe
  • question-first witness SHA-256: a7976057c26051fab92342fc95d48af224466c0e1e4ab6ae4c8811c02772e6da
  • Lean: NOT_RUN · human review: NOT_PERFORMED
Same-source full JSON