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Question 2366: A Short Exact Orbit of the Specified Logistic Increment Model

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

R0003-02366 · q-20261013-advance-20261021-r07-discrete-logistic-growth-0041

Original question and givens

Use exactly the fixed discrete increment model next=x+r*x*(1−x/K), with K>0, 0≤r≤1 and 0≤x≤K, at fixed time steps. Reduce exact rational outputs and omit /1 for integers. This is neither another logistic-map convention nor a continuous logistic solution; a finite orbit proves no stability, convergence or empirical population fit. initial=15/25, rate=0/1, capacity=5/1, updates=2. Give (initial,rate,capacity,update count,orbit including initial). With zero updates retain just the initial value.

  • G001 — Use exactly the fixed discrete increment model next=x+r*x*(1−x/K), with K>0, 0≤r≤1 and 0≤x≤K, at fixed time steps. Reduce exact rational outputs and omit /1 for integers. This is neither another logistic-map convention nor a continuous logistic solution; a finite orbit proves no stability, convergence or empirical population fit. initial=15/25, rate=0/1, capacity=5/1, updates=2. Give (initial,rate,capacity,update count,orbit including initial). With zero updates retain just the initial value.

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

0≤r=0≤1; K=5>0; 0≤x=3/5≤K

After

T(x)=x+r·x·(1−x/K)

Conditions: none

This fixed model adds the increment to the old state;it is not the different direct-product map r·x·(1−x/K).

Step identifiers and dependencies

Rule: logistic_increment_model · Uses: G001

S002 · implies

Before

initial=3/5; steps=2

After

retain the initial state before updating

Conditions: none

A zero-transition prefix still contains its initial state.

Step identifiers and dependencies

Rule: logistic_orbit_initial · Uses: G001, S001

S003 · calculation

Before

x/K at step1 := div(3/5, 5)

After

x/K at step1 = 3/25

Conditions: none

Positive K permits normalization of the state.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S002

S004 · calculation

Before

1−x/K at step1 := sub(1, 3/25)

After

1−x/K at step1 = 22/25

Conditions: none

This feedback factor is nonnegative in the declared interval.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S003

S005 · calculation

Before

x(1−x/K) at step1 := mul(3/5, 22/25)

After

x(1−x/K) at step1 = 66/125

Conditions: none

Multiply the current state by the remaining proportion first.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S004

S006 · calculation

Before

increment at step1 := mul(0, 66/125)

After

increment at step1 = 0

Conditions: none

Then multiply by the increment rate r.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S005

S007 · calculation

Before

next state at step1 := sum(3/5, 0)

After

next state at step1 = 3/5

Conditions: none

Add the original x back;the addition must not be omitted.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S006

S008 · implies

Before

T(x)−x=r·x·(1−x/K)≥0; K−T(x)=(K−x)(1−r·x/K)≥0

After

0≤3/5≤5

Conditions: none

The factor inequalities follow from0≤r≤1 and0≤x≤K,proving interval preservation for this model rather than guessing from samples.

Step identifiers and dependencies

Rule: qualified_interval_preservation · Uses: G001, S007

S009 · calculation

Before

x/K at step2 := div(3/5, 5)

After

x/K at step2 = 3/25

Conditions: none

Positive K permits normalization of the state.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S008

S010 · calculation

Before

1−x/K at step2 := sub(1, 3/25)

After

1−x/K at step2 = 22/25

Conditions: none

This feedback factor is nonnegative in the declared interval.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S009

S011 · calculation

Before

x(1−x/K) at step2 := mul(3/5, 22/25)

After

x(1−x/K) at step2 = 66/125

Conditions: none

Multiply the current state by the remaining proportion first.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S010

S012 · calculation

Before

increment at step2 := mul(0, 66/125)

After

increment at step2 = 0

Conditions: none

Then multiply by the increment rate r.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S011

S013 · calculation

Before

next state at step2 := sum(3/5, 0)

After

next state at step2 = 3/5

Conditions: none

Add the original x back;the addition must not be omitted.

Step identifiers and dependencies

Rule: exact_rational_arithmetic · Uses: G001, S012

S014 · implies

Before

T(x)−x=r·x·(1−x/K)≥0; K−T(x)=(K−x)(1−r·x/K)≥0

After

0≤3/5≤5

Conditions: none

The factor inequalities follow from0≤r≤1 and0≤x≤K,proving interval preservation for this model rather than guessing from samples.

Step identifiers and dependencies

Rule: qualified_interval_preservation · Uses: G001, S013

S015 · implies

Before

orbit=[3/5, 3/5, 3/5]

After

entries=3=steps+1

Conditions: none

This is an exact finite orbit,not a stability proof,empirical prediction or model-fit evidence.

Step identifiers and dependencies

Rule: logistic_prefix_scope · Uses: G001, S014

Reverse checks

  • 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.
  • S013 · premise_and_result_audit — Recompute next state at step2 with exact rational arithmetic, not rounded decimals.
  • S012 · premise_and_result_audit — Recompute increment at step2 with exact rational arithmetic, not rounded decimals.
  • S011 · premise_and_result_audit — Recompute x(1−x/K) at step2 with exact rational arithmetic, not rounded decimals.
  • S010 · premise_and_result_audit — Recompute 1−x/K at step2 with exact rational arithmetic, not rounded decimals.
  • S009 · premise_and_result_audit — Recompute x/K at step2 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 — Recompute next state at step1 with exact rational arithmetic, not rounded decimals.
  • S006 · premise_and_result_audit — Recompute increment at step1 with exact rational arithmetic, not rounded decimals.
  • S005 · premise_and_result_audit — Recompute x(1−x/K) at step1 with exact rational arithmetic, not rounded decimals.
  • S004 · premise_and_result_audit — Recompute 1−x/K at step1 with exact rational arithmetic, not rounded decimals.
  • S003 · premise_and_result_audit — Recompute x/K at step1 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 — Check against the original data and this step's premises; a one-way implication is not an equivalence.

Result

(3/5, 0, 5, 2, [3/5, 3/5, 3/5])

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: f423f08e6bf1b93080aa04da32e2b25ecae01096215bb2c38503d9c9e4ce1723
  • candidate record SHA-256: c536b1d19d0a6ac5418712bac57e025429a73fae409095e8d7f8920845d034f6
  • semantic review receipt SHA-256: 5dbc70ebd5f74b23384c93b63a2b1d6519e206c79f22ae16a6c2d7483cea783f
  • question-first witness SHA-256: cf121c8dd2fec13aa118b04b049ee39494f1d6d9ecdc13514cafb78c0fc021fa
  • Lean: NOT_RUN · human review: NOT_PERFORMED
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