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Question 11373: A Finite Path Includes Its Initial-State Mass

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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R0021-11373 · q-20261013-advance-20261024-r03-finite-markov-chain-0098

Original question and givens

Use one fixed finite time-homogeneous transition table=[[23/25, 2/25], [12/13, 1/13]]. Rows denote the current state and columns the next state; row entries must be nonnegative and sum exactly to 1 before stepping. State order stays fixed. Use exact rational arithmetic, reduce fractions to positive denominators and omit /1 for integer outputs. No stationary, irreducibility, ergodicity or long-term convergence claim follows. Require initial law=[23/24, 1/24] to be a qualified PMF. Nonempty path=[0, 1, 0]. Give (path,[initial mass,each successive transition factor],product). A one-state path has only its initial-mass factor.

  • G001 — Use one fixed finite time-homogeneous transition table=[[23/25, 2/25], [12/13, 1/13]]. Rows denote the current state and columns the next state; row entries must be nonnegative and sum exactly to 1 before stepping. State order stays fixed. Use exact rational arithmetic, reduce fractions to positive denominators and omit /1 for integer outputs. No stationary, irreducibility, ergodicity or long-term convergence claim follows. Require initial law=[23/24, 1/24] to be a qualified PMF. Nonempty path=[0, 1, 0]. Give (path,[initial mass,each successive transition factor],product). A one-state path has only its initial-mass factor.

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

transition row0:raw rational pairs=[[23, 25], [2, 25]]

After

transition row0:normalized=[23/25, 2/25]

Conditions: none

Every original denominator must be nonzero.Reduce fractions to positive denominators without decimal approximation.

Step identifiers and dependencies

Rule: exact_weight_normalization · Uses: G001

S002 · calculation

Before

transition row0 total := sum(23/25, 2/25)

After

transition row0 total = 1

Conditions: none

Compute exactly with this step's specified roles,retaining signs,denominators and original pairings.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S001

S003 · implies

Before

transition row0:weights=[23/25, 2/25];sum=1

After

nonnegative=Yes;total_one=Yes;qualified=Yes

Conditions: none

Check nonnegativity and exact total one separately.Zero weights are allowed;negative weights or near-one totals are not repaired.

Step identifiers and dependencies

Rule: separate_weight_guards · Uses: G001, S002

S004 · implies

Before

transition row1:raw rational pairs=[[12, 13], [1, 13]]

After

transition row1:normalized=[12/13, 1/13]

Conditions: none

Every original denominator must be nonzero.Reduce fractions to positive denominators without decimal approximation.

Step identifiers and dependencies

Rule: exact_weight_normalization · Uses: G001, S003

S005 · calculation

Before

transition row1 total := sum(12/13, 1/13)

After

transition row1 total = 1

Conditions: none

Compute exactly with this step's specified roles,retaining signs,denominators and original pairings.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · implies

Before

transition row1:weights=[12/13, 1/13];sum=1

After

nonnegative=Yes;total_one=Yes;qualified=Yes

Conditions: none

Check nonnegativity and exact total one separately.Zero weights are allowed;negative weights or near-one totals are not repaired.

Step identifiers and dependencies

Rule: separate_weight_guards · Uses: G001, S005

S007 · implies

Before

complete transition matrix=[[23/25, 2/25], [12/13, 1/13]];row sums=[1, 1]

After

nonnegative=Yes;row_stochastic=Yes;rows=current state, columns=next state

Conditions: none

Every complete row must be nonnegative with exact sum1;column sums are not the convention.This fixed time-homogeneous Markov model gives no stationary,ergodic or long-term convergence theorem.

Step identifiers and dependencies

Rule: whole_row_stochastic_kernel_convention · Uses: G001, S006

S008 · implies

Before

initial law:raw rational pairs=[[23, 24], [1, 24]]

After

initial law:normalized=[23/24, 1/24]

Conditions: none

Every original denominator must be nonzero.Reduce fractions to positive denominators without decimal approximation.

Step identifiers and dependencies

Rule: exact_weight_normalization · Uses: G001, S007

S009 · calculation

Before

initial law total := sum(23/24, 1/24)

After

initial law total = 1

Conditions: none

Compute exactly with this step's specified roles,retaining signs,denominators and original pairings.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S008

S010 · implies

Before

initial law:weights=[23/24, 1/24];sum=1

After

nonnegative=Yes;total_one=Yes;qualified=Yes

Conditions: none

Check nonnegativity and exact total one separately.Zero weights are allowed;negative weights or near-one totals are not repaired.

Step identifiers and dependencies

Rule: separate_weight_guards · Uses: G001, S009

S011 · implies

Before

path=[0, 1, 0];initial law=[23/24, 1/24]

After

factor0=initial[0]=23/24

Conditions: none

The path event includes its first state.Start with its initial mass;a one-state path has only this factor.

Step identifiers and dependencies

Rule: path_includes_initial_state_mass · Uses: G001, S010

S012 · implies

Before

path step=1;current=0;next=1

After

factor1=P[0][1]=2/25

Conditions: none

Read current row,next-state column in original path order.Zero probabilities may be product factors;do not divide by a zero-probability event.

Step identifiers and dependencies

Rule: path_ordered_transition_factor · Uses: G001, S011

S013 · implies

Before

path step=2;current=1;next=0

After

factor2=P[1][0]=12/13

Conditions: none

Read current row,next-state column in original path order.Zero probabilities may be product factors;do not divide by a zero-probability event.

Step identifiers and dependencies

Rule: path_ordered_transition_factor · Uses: G001, S012

S014 · calculation

Before

path prefix product1 := mul(23/24, 2/25)

After

path prefix product1 = 23/300

Conditions: none

Compute exactly with this step's specified roles,retaining signs,denominators and original pairings.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S013

S015 · calculation

Before

path prefix product2 := mul(23/300, 12/13)

After

path prefix product2 = 23/325

Conditions: none

Compute exactly with this step's specified roles,retaining signs,denominators and original pairings.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S014

S016 · implies

Before

ordered path factors=[23/24, 2/25, 12/13]

After

finite path probability=23/325

Conditions: none

Use this model's finite-path product:initial mass times every transition.This does not assign the Markov property to arbitrary stochastic processes.

Step identifiers and dependencies

Rule: finite_markov_path_joint_probability · Uses: G001, S015

Reverse checks

  • 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 — Recompute path prefix product2 with exact rational arithmetic, not rounded decimals.
  • S014 · premise_and_result_audit — Recompute path prefix product1 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 — 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S009 · premise_and_result_audit — Recompute initial law total with exact rational arithmetic, not rounded decimals.
  • S008 · premise_and_result_audit — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S005 · premise_and_result_audit — Recompute transition row1 total with exact rational arithmetic, not rounded decimals.
  • 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S002 · premise_and_result_audit — Recompute transition row0 total with exact rational arithmetic, not rounded decimals.
  • 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, 0], [23/24, 2/25, 12/13], 23/325)

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: c142940e2a5ba179cf6516dd64d522973978d06aa5d0e9f9dc7564ec34feac43
  • candidate record SHA-256: 4df0fc9ed0ce5b5111367ccdf070549328f6f26ceb59fb2f249aa27a1c234e06
  • semantic review receipt SHA-256: 47d23d3735987d68e27733b051bdfa80a3616d44fb223b82bf2e6c8e46d49258
  • question-first witness SHA-256: a857db558000724020d2d5e815cb6bc3e2c9e2933df295bf33eb478d3c695139
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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