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Question 10800: A Two-Time Joint Distribution Keeps the Requested Time Order

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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← Question derivation index · Original question batch

R0020-10800 · q-20261013-advance-20261023-r06-discrete-stochastic-process-0100

Original question and givens

Use one common finite probability space specified by the complete distinct equal-horizon path list=[[24, 24, 25], [24, 25, 25], [25, 25, 24]] and aligned exact masses=[1/4, 1/4, 1/2]. Preserve the original path-mass pairing. A qualified joint path law has nonnegative masses summing exactly to 1. Time starts at 0. Marginals do not determine the joint law or Markov property; a finite horizon gives no stationarity, ergodicity or infinite-time extension. Use exact reduced rational outputs with positive denominators, omitting /1 for integers. Require a qualified law. time_a=0, time_b=1. Give (time_a,time_b,every [[state at time_a,state at time_b],aggregated mass] row). Order distinct output pairs by the source’s en-locale comparison of their JSON strings, not numeric coordinate sorting. Equal requested times are allowed.

  • G001 — Use one common finite probability space specified by the complete distinct equal-horizon path list=[[24, 24, 25], [24, 25, 25], [25, 25, 24]] and aligned exact masses=[1/4, 1/4, 1/2]. Preserve the original path-mass pairing. A qualified joint path law has nonnegative masses summing exactly to 1. Time starts at 0. Marginals do not determine the joint law or Markov property; a finite horizon gives no stationarity, ergodicity or infinite-time extension. Use exact reduced rational outputs with positive denominators, omitting /1 for integers. Require a qualified law. time_a=0, time_b=1. Give (time_a,time_b,every [[state at time_a,state at time_b],aggregated mass] row). Order distinct output pairs by the source’s en-locale comparison of their JSON strings, not numeric coordinate sorting. Equal requested times are allowed.

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

original support index=0;path=[24, 24, 25];raw mass=[1, 4]

After

aligned reduced mass=1/4

Conditions: none

Complete paths are distinct and share one positive horizon.Masses remain paired to original support indices.Reduce fractions only:do not sort paths or divide by a total to repair an unqualified candidate.

Step identifiers and dependencies

Rule: path_mass_original_support_pairing · Uses: G001

S002 · implies

Before

original support index=1;path=[24, 25, 25];raw mass=[1, 4]

After

aligned reduced mass=1/4

Conditions: none

Complete paths are distinct and share one positive horizon.Masses remain paired to original support indices.Reduce fractions only:do not sort paths or divide by a total to repair an unqualified candidate.

Step identifiers and dependencies

Rule: path_mass_original_support_pairing · Uses: G001, S001

S003 · implies

Before

original support index=2;path=[25, 25, 24];raw mass=[1, 2]

After

aligned reduced mass=1/2

Conditions: none

Complete paths are distinct and share one positive horizon.Masses remain paired to original support indices.Reduce fractions only:do not sort paths or divide by a total to repair an unqualified candidate.

Step identifiers and dependencies

Rule: path_mass_original_support_pairing · Uses: G001, S002

S004 · calculation

Before

whole path-law mass sum := sum(1/4, 1/4, 1/2)

After

whole path-law mass sum = 1

Conditions: none

Compute exactly with this step's original roles and operands,without floating approximation or reordering source data.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · implies

Before

horizon=3;normalized aligned masses=[1/4, 1/4, 1/2]

After

all nonnegative=Yes;total=1;qualified joint law=Yes

Conditions: none

The qualification task may retain negative or unnormalized masses to report failure.Marginal/event/joint queries require the whole law nonnegative with total exactly1.A finite horizon establishes neither Markov behavior nor stationarity.

Step identifiers and dependencies

Rule: whole_finite_joint_law_qualification · Uses: G001, S004

S006 · calculation

Before

joint path0 bucket update := sum(0, 1/4)

After

joint path0 bucket update = 1/4

Conditions: none

Compute exactly with this step's original roles and operands,without floating approximation or reordering source data.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S005

S007 · implies

Before

support index=0;ordered times=[0, 1];ordered state pair=[24, 24];original mass=1/4;previous bucket=0

After

updated pair mass=1/4

Conditions: none

Keep time_a first and time_b second;equal times are allowed.Do not replace path-based joint mass by a product of marginals.

Step identifiers and dependencies

Rule: joint_original_time_order_and_mass_pairing · Uses: G001, S006

S008 · calculation

Before

joint path1 bucket update := sum(0, 1/4)

After

joint path1 bucket update = 1/4

Conditions: none

Compute exactly with this step's original roles and operands,without floating approximation or reordering source data.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S007

S009 · implies

Before

support index=1;ordered times=[0, 1];ordered state pair=[24, 25];original mass=1/4;previous bucket=0

After

updated pair mass=1/4

Conditions: none

Keep time_a first and time_b second;equal times are allowed.Do not replace path-based joint mass by a product of marginals.

Step identifiers and dependencies

Rule: joint_original_time_order_and_mass_pairing · Uses: G001, S008

S010 · calculation

Before

joint path2 bucket update := sum(0, 1/2)

After

joint path2 bucket update = 1/2

Conditions: none

Compute exactly with this step's original roles and operands,without floating approximation or reordering source data.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S009

S011 · implies

Before

support index=2;ordered times=[0, 1];ordered state pair=[25, 25];original mass=1/2;previous bucket=0

After

updated pair mass=1/2

Conditions: none

Keep time_a first and time_b second;equal times are allowed.Do not replace path-based joint mass by a product of marginals.

Step identifiers and dependencies

Rule: joint_original_time_order_and_mass_pairing · Uses: G001, S010

S012 · implies

Before

ordered times=[0, 1];distinct JSON pair keys=["[24,24]","[24,25]","[25,25]"]

After

en-locale JSON-string ordered joint rows=[[[24, 24], 1/4], [[24, 25], 1/4], [[25, 25], 1/2]]

Conditions: none

Order by English-locale comparison of each pair's JSON string,not numeric coordinate order.This orders presentation only,without changing a pair or its mass.

Step identifiers and dependencies

Rule: joint_pair_source_locale_order · Uses: G001, S011

Reverse checks

  • S012 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • 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 path2 bucket update 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 path1 bucket update with exact rational arithmetic, not rounded decimals.
  • S007 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S006 · premise_and_result_audit — Recompute joint path0 bucket update with exact rational arithmetic, not rounded decimals.
  • S005 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S004 · premise_and_result_audit — Recompute whole path-law mass sum 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.

Result

(0, 1, [[[24, 24], 1/4], [[24, 25], 1/4], [[25, 25], 1/2]])

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: e32e21e023395a3b068e09bbf19a47b48ef363648362bbbc9c04af0bd4ece8d6
  • candidate record SHA-256: beb2f5a2e46840dce0b78ff0c54581c4a2350e1d9438e150f2a2a9beaf562e1c
  • semantic review receipt SHA-256: b4c47938fd38085d44967226cfa8337d61334455472e7307c60d3a488cef598f
  • question-first witness SHA-256: 3c23baa97a5933bc07b44f2257017ef4e845bf1429bd6f5381410681c43b97e4
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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